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Tytuł:
Performance analysis of doppler aided GPS/QZSS precise positioning for land vehicles
Autorzy:
Lee, B. H.
Jee, G. I.
Powiązania:
https://bibliotekanauki.pl/articles/320665.pdf
Data publikacji:
2013
Wydawca:
Polskie Forum Nawigacyjne
Tematy:
QZSS
land navigation
intelligent transport systems
Opis:
For ITS (Intelligent Transport Systems), especially for land vehicles, precise position is the prime information. GNSS is the most popular navigation system. Generally, ITS demands lane distinguishable positioning accuracy. However urban area is most environments of land vehicles and the signal blocks of satellite with low elevation angle, multipath error and etc. make unreliable positioning results. Especially, lack of number of visible satellites (fewer than 4 satellites) cannot provide positioning results. QZSS (Quasi-Zenith Satellite System) which operated by Japan has high interoperability. In addition, its elevation angle is very high in long time in Korea. It means QZSS signal can be received in urban area and it can be great advantage for land vehicles. The most positioning errors are occurred by multipath, cycle slip, and etc. For example, multipath error is unexpected momentary error. In order to reduce position error, smoothing technique in position domain is needed. In this paper, precise positioning for land vehicles was evaluated. First, by using QZSS, probability of navigation solution was enhanced. Second, the reliability is improved by smoothing positioning result using Doppler measurement. The analysis was performed by trajectory analysis using precise map data.
Dla inteligentnych systemów transportowych, zwłaszcza w odniesieniu do pojazdów lądowych, dokładna informacja o pozycji jest pierwszorzędna. Systemy satelitarne (GNSS) to obecnie najbardziej popularne systemy nawigacyjne. Zasadniczo inteligentne systemy transportowe wymagają znajomości pozycji determinowanej warunkami drogowymi, a obszary miejskie stanowią środowisko, w którym porusza się największa liczba pojazdów lądowych. Takie ograniczenia, jak przesłanianie niskich satelitów, błąd wielodrożności i tym podobne powodują, że pozycje wyznaczane metodami satelitarnymi stają się mało wiarygodne. Brak wyznaczeń może być spowodowany zwłaszcza brakiem dostatecznej liczby widocznych satelitów (mniej niż cztery). QZSS (Quasi-Zenitalny System Satelitarny), uruchomiony w Japonii, cechuje się w tym względzie niezwykle korzystnymi cechami. W dodatku jego wysokość topocentryczna przez długi czas jest bardzo duża dla obserwatora znajdującego się w Korei. Oznacza to, że sygnał tego systemu może być odbierany w obszarze miejskim, co stanowi bardzo korzystną cechę dla pojazdów lądowych. Większość błędów pozycji wynika w tym wypadku z błędu wielodrogowości, przeskoków fazy i tym podobnych. Na przykład, wielodrogowość obrazuje się jako chwilowe, niespodziewane odchylenie pozycji. Dla zmniejszenia tego rodzaju błędów niezbędna jest technika wygładzania pozycji. W artykule ocenie poddano dokładność pozycjonowania pojazdów lądowych. Po pierwsze poprzez zastosowanie QZSS poprawiono prawdopodobieństwo poprawnego rozwiązania, po drugie poprzez zastosowanie technik wygładzania z użyciem pomiarów dopplerowskich poprawiono wiarygodność wyznaczeń. Analizy wyników dokonano przez analizę trajektorii, odnosząc ją do dokładnych danych mapy.
Źródło:
Annual of Navigation; 2013, 20; 85-96
1640-8632
Pojawia się w:
Annual of Navigation
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Atomistic Analysis Of Radiation-Induced Segregation In Ion-Irradiated Stainless Steel 316
Analiza w skali atomowej indukowanej promieniowaniem segregacji w stali nierdzewnej 316
Autorzy:
Lee, G.-G.
Jin, H.-H.
Chang, K.
Lee, B. H.
Kwon, J.
Powiązania:
https://bibliotekanauki.pl/articles/354713.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
atom probe tomography (APT)
radiation-induced segregation (RIS)
ion irradiation
irradiation defects
stainless steel
APT
RIS
stal nierdzewna
segregacja
Opis:
Stainless steel (SS) is a well-known material for the internal parts of nuclear power plants. It is known that these alloys exhibit radiation-induced segregation (RIS) at point defect sinks at moderate temperature, while in service. The RIS behavior of SS can be a potential problem by increasing the susceptibility to irradiation-assisted stress corrosion cracking. In this work, the RIS behavior of solute atoms at sinks in SS 316 irradiated with Fe4+ ions were characterized by atom probe tomography (APT). There were torus-shaped defects along with a depletion of Cr and enrichment of Ni and Si. These clusters are believed to be dislocation loops resulting from irradiation. The segregation of solutes was also observed for various defect shapes. These observations are consistent with other APT results from the literature. The composition of the clusters was analyzed quantitatively almost at the atomic scale. Despite the limitations of the experiments, the APT analysis was well suited for discovering the structure of irradiation defects and performing a quantitative analysis of RIS in irradiated specimens.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1179-1184
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multistep Heat-Treatment Effects on Electrospun Nd-Fe-B-O Nanofibers
Autorzy:
Jeon, E. J.
Eom, N. S. A.
Lee, J.
Lee, B.
Cho, H. M.
On, J. S.
Choa, Y.-H
Kim, B. S.
Powiązania:
https://bibliotekanauki.pl/articles/354311.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B
nanofibers
electrospinning
heat treatment
Opis:
Neodymium-Iron-Boron (Nd-Fe-B) magnets are considered to have the highest energy density, and their applications include electric motors, generators, hard disc drives, and MRI. It is well known that a fiber structure with a high aspect ratio and the large specific surface area has the potential to overcome the limitations, such as inhomogeneous structures and the difficulty in alignment of easy axis, associated with such magnets obtained by conventional methods. I n this work, a suitable heat-treatment procedure based on single-step and multistep treatments to synthesize sound electrospun Nd-Fe-B-O nanofibers of Φ572 nm was investigated. The single-step heat-treated (directly heat-treated at 800°C for 2 h in air) samples disintegrated along with the residual organic compounds, whereas the multistep heat-treated (sequential three-step heat-treated including three steps;: dehydration (250°C for 30 min in an inert atmosphere), debinding (650°C for 30 min in air), and calcination (800°C for 1 h in air)) fibers maintained sound fibrous morphology without any organic impurities. They could maintain such fibrous morphologies during the dehydration and debinding steps because of the relatively low internal pressures of water vapor and polymer, respectively. In addition, the NdFeO3 alloying phase was dominant in the multistep heat-treated fibers due to the removal of barriers to mass transfer in the interparticles.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1433-1437
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of Mo-Si-B Intermetallic Compound Powders Under Different Heat Treatment Conditions
Autorzy:
Park, J. H.
Lee, S.
Kim, D.
Kim, Y.
Yang, S. H.
Lee, S. H.
Powiązania:
https://bibliotekanauki.pl/articles/353369.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Mo-Si-B alloys
intermetallic compounds
reitveld refinement
T2 phase
A15 phase
Opis:
In this research, we investigated the effects of reduction atmospheres on the creation of the Mo-Si-B intermetallic compounds (IMC) during the heat treatments. For outstanding anti-oxidation and elevated mechanical strength at the ultrahigh temperature, we fabricated the uniformly dispersed IMC powders such as Mo5SiB2 (T2) and Mo3Si (A15) phases using the two steps of chemical reactions. Especially, in the second procedure, we studied the influence of the atmospheres (e.g. vacuum, argon, and hydrogen) on the synthesis of IMCs during the reduction. Furthermore, the newly produced IMCs were observed by SEM, XRD, and EDS to identify the phase of the compounds. We also calculated an amount of IMCs in the reduced powders depending on the atmosphere using the Reitveld refinement method. Consequently, it is found that hydrogen atmosphere was suitable for fabrication of IMC without other IMC phases.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1509-1512
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Characterization of CoCrFeNiMn High Entropy Alloy Powder Processed by Gas Atomization
Autorzy:
Park, T. G.
Lee, S. H.
Lee, B.
Cho, H. M.
Choi, W. J.
Kim, B. S.
Shin, K. S.
Kim, T.-S.
Powiązania:
https://bibliotekanauki.pl/articles/353649.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high entropy alloy
gas atomization
spark plasma sintering
CoCrFeNiMn
Opis:
In this study, precisely controlled large scale gas atomization process was applied to produce spherical and uniform shaped high entropy alloy powder. The gas atomization process was carried out to fabricate CoCrFeNiMn alloy, which was studied for high ductility and mechanical properties at low temperatures. It was confirmed that the mass scale, single phase, equiatomic, and high purity spherical high entropy alloy powder was produced by gas atomization process. The powder was sintered by spark plasma sintering process with various sintering conditions, and mechanical properties were characterized. Through this research, we have developed a mass production process of high quality and spherical high entropy alloy powder, and it is expected to expand applications of this high entropy alloy into fields such as powder injection molding and 3D printing for complex shaped components.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 1055-1059
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of acute lipopolysaccharide-induced toxemia model on some neglected blood parameters
Autorzy:
Adam, G.O.
Lee, H.R.
Lee, S.J.
Kim, S.J.
Kim, G.B.
Kang, H.S.
Powiązania:
https://bibliotekanauki.pl/articles/2087627.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Toxemia
lipopolysaccharide
base excess
pH
animal model
Źródło:
Polish Journal of Veterinary Sciences; 2018, 21, 4; 665-671
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, Structure, Photoluminescence, and Raman Spectrum of Indium Oxide Nanowires
Autorzy:
Kim, H.
Na, H.
Yang, J.
Lee,, C.
Powiązania:
https://bibliotekanauki.pl/articles/1505485.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
78.55.-m
Opis:
Production of indium oxide $(In_2O_3)$ whiskers at a very low temperature of 650°C was reported. The synthetic route was comprised of a thermal heating process of a mixture of In and Mg powders. We have investigated the structural properties of the as-synthesized nanowires by using X-ray diffraction and scanning electron microscopy. The product consisted of one-dimensional nanowires, with a crystalline cubic structure of $In_2O_3$. The photoluminescence measurement with the Gaussian fitting exhibited visible light emission bands centered at 2.1 eV and 2.8 eV. The peaks of the Raman spectrum were indexed to the modes being associated with cubic $In_2O_3$.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 143-145
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence Studies of Aluminum Nitride Nanowires
Autorzy:
Yang, J.
Na, H.
Kim, H.
Kebede, M.
Choi, R.
Jeong, J.
Lee, C.
Powiązania:
https://bibliotekanauki.pl/articles/1505466.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
78.55.-m
Opis:
We report the production of AlN nanowires by the thermal heating method, for exploring their photoluminescence properties. The room-temperature photoluminescence properties were investigated with different annealing environment. While broad emissions with peaks at around 2.45 and 2.95 eV were obtained from both unannealed and annealed samples, the additional 2.1 eV peak was found from the annealed samples. We have suggested the possible emission mechanisms based on the assumption that both 2.45 eV peak and 2.1 eV peak are ascribed to the nitrogen vacancies. Annealing in N_2 environment exhibited lower intensities of 2.45 eV peak and 2.1 eV peak in comparison to those in Ar environment, presumably due to the suppression of nitrogen vacancies.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 125-127
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
$SiO_x$ Nanowires Produced on Molybdenum-Coated Si Substrates
Autorzy:
Kim, H.
Lee, J.
Yang, J.
Powiązania:
https://bibliotekanauki.pl/articles/1813396.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
78.55.-m
Opis:
We synthesized $SiO_x$ nanowires with diameters of 30-140 nm, for the first time by the simple heating of the Mo-coated Si substrates. X-ray diffraction, selected area electron diffraction, and energy-dispersive X-ray spectroscopy indicated that the nanowires were in an amorphous state, comprising Si and O only. Fitting the photoluminescence spectrum with Gaussian functions revealed that the nanowires exhibited significant photoluminescence intensities near blue and green light regions. We extensively discussed the possible growth mechanism of $SiO_x$ nanowires.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 1017-1020
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Magnetic Properties of NdFeB Sintered Magnets Diffusion-Treated with Cu/Al Mixed Dyco Alloy-Powder
Autorzy:
Lee, M.-W.
Bae, K.-H.
Lee, S.-R.
Kim, H.-J.
Jang, T.-S.
Powiązania:
https://bibliotekanauki.pl/articles/353351.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B sintered magnets
grain boundary diffusion process
low melting point element
DyCo alloy-powder diffusion
Opis:
We investigated the microstructural and magnetic property changes of DyCo, Cu + DyCo, and Al + DyCo diffusion-treated NdFeB sintered magnets. The coercivity of all diffusion treated magnet was increased at 880ºC of 1st post annealing(PA), by 6.1 kOe in Cu and 7.0 kOe in Al mixed DyCo coated magnets, whereas this increment was found to be relatively low (3.9 kOe) in the magnet coated with DyCo only. The diffusivity and diffusion depth of Dy were increased in those magnets which were treated with Cu or Al mixed DyCo, mainly due to comparatively easy diffusion path provided by Cu and Al because of their solubility with Ndrich grain boundary phase. The formation of Cu/Al-rich grain boundary phase might have enhanced the diffusivity of Dy-atoms. Moreover, relatively a large number of Dy atoms reached into the magnet and mostly segregated at the interface of Nd2 Fe14 B and grain boundary phases covering Nd2 Fe14 B grains so that the core-shell type structures were developed. The formation of highly anisotropic (Nd, Dy)2Fe14B phase layer, which acted as the shell in the core-shell type structure so as to prevent the reverse domain movement, was the cause of enhancing the coercivity of diffusion treated NdFeB magnets. Segregation of cobalt in Nd-rich TJP followed by the formation of Co-rich phase was beneficial for the coercivity enhancement, resulting in the stabilization of the metastable c-Nd2O3 phase.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1263-1266
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristics Of The Porous Body Sintered By Nano-Sized Fe-Cr-Al Alloy Powder
Charakterystyka porowatego korpusu spiekanego z nanometrycznego proszku stopu Fe-Cr-Al
Autorzy:
Lee, S.-I.
Lee, S.-H.
Gu, B.-U.
Lee, D.-W.
Kim, B.-K.
Powiązania:
https://bibliotekanauki.pl/articles/356635.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fe-Cr-Al powder
metallic sponges
sintering temperature
oxidation resistance
proszek Fe-Cr-Al
proszek nanometryczny
temperatura spiekania
odporność na utlenianie
Opis:
Porous metal with uniform honeycomb structure was successfully produced by sintering using Fe-Cr-Al nano powder, which was prepared by the pulsed wire evaporation (PWE) in ethanol. Its process consisted of the several steps; 1) coating on the surface of polyurethane sponge with the liquid droplets generated from the ethanol-based slurry where the Fe-Cr-Al nano powders were uniformly dispersed, 2) heat treatment of debinding to remove the polyurethane sponge and 3) sintering of the porous green body formed by Fe-Cr-Al nano powders. The strut thickness of porous Fe-Cr-Al was increased by the increase of spraying times in ESP step. Also, The shrinkages and the oxidation resistance of the sintered porous body was increased with increase of sintering temperature. The optimal sintering temperature was shown to 1450°C in views to maximize the oxidation resistance and sinterability.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1275-1279
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantitative Analysis of Cryomilled Nanocrystalline Ti-6Al-4V Alloy Powder by X-Ray Diffraction
Autorzy:
Oh, M.
Yu, H. K.
Lee, J.-H.
Oh, M. C.
Jung, S.-H.
Ahn, B.
Powiązania:
https://bibliotekanauki.pl/articles/356265.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nanocrystalline
cryomilling
Ti alloy
X-ray diffraction
size-strain plot method
Opis:
A nanocrystalline Ti alloy powder was fabricated using cryomilling. The grain size and lattice strain evolution during cryomilling were quantitatively analyzed using X-ray diffraction (XRD) based on the Scherrer equation, Williamson-Hall (W-H) plotting method, and size-strain (S-S) method assuming uniform deformation. Other physical parameters including stress and strain have been calculated. The average crystallite size and the lattice strain evaluated from XRD analysis are in good agreement with the result of transmission electron microscopy (TEM).
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1439-1442
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compositional Dependence of Hardness of Ge-Sb-Se Glass for Molded Lens Applications
Zależność stężeniowa twardości szkła Ge-Sb-Se do zastosowań na formowane soczewki
Autorzy:
Park, J. K.
Lee, J. H.
Shin, S. Y.
Yi, J. H.
Lee, W. H.
Park, B. J.
Choi, J. H.
Kim, N. Y.
Choi, Y. G.
Powiązania:
https://bibliotekanauki.pl/articles/352228.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chalcogenide glasses
Ge-Sb-Se glass
infrared lens
molded lens
infrared camera
szkło
Ge-Sb-Se
soczewki formowane
twardość szkła
kamera termowizyjna
Opis:
Chalcogenide glass in the ternary Ge-Sb-Se system is inherently moldable, thus being considered as a strong candidate material for use in infrared-transmitting lens applications from the viewpoint of thermal and mechanical stability. In an effort to experimentally determine compositional region suitable for the molded lens applications, we evaluate its compositional dependence of hardness. Among the constituent atoms, Ge content turns out to exert a most conspicuous correlation with hardness. This phenomenological behavior is then explained in connection with the structural evolution that Ge brings about.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1205-1208
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect Of The Desorption-Recombination Temperature On The Microstructure And Magnetic Properties Of HDDR Processed Nd-Fe-B Powders
Wpływ temperatury desorpcji-rekombinacji na mikrostrukturę i właściwości magnetyczne proszków Nd-Fe-B przetwarzanych metodą HDDR
Autorzy:
Lee, J.-G.
Cha, H.-R.
Liu, S.
Yu, J.-H.
Baek, Y.-K.
Kwon, H.-W.
Powiązania:
https://bibliotekanauki.pl/articles/353723.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B
HDDR
permanent magnet
grain boundary
metoda HDDR
magnes trwały
granica ziarna
Opis:
The effect of the desorption-recombination temperature on the microstructure and magnetic properties of hydrogenation-disproportionation-desorption-recombination (HDDR) processed Nd-Fe-B powders was studied. The NdxB6.4Ga0.3Nb20.2Febal (x=12.5-13.5, at.%) casting alloys were pulverized after homogenizing annealing, and then subjected to HDDR treatment. During the HDDR process, desorption-recombination (DR) reaction was induced at two different temperature, 810°C and 820°C. The higher Nd content resulted in enhanced coercivity of the HDDR powder, and which was attributed to the thicker and more uniform Nd-rich phase along grain boundaries. But this uniform Nd-rich phase induced faster grain growth. The remanence of the powder DR-treated at 820°C is higher than that DR-treated at 810°C. In addition, it was also confirmed that higher DR temperature is much more effective to improve squareness.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1499-1501
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Compression Properties of Fe-Cr-B Alloy Manufactured using Laser Metal Deposition
Autorzy:
Joo, Y.-A.
Yoon, T.-S.
Park, S.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/352075.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Fe-Cr-B composite
laser Metal Deposition
bulk type
microstructure
compressive properties
Opis:
Fe-Cr-B alloy is a material with precipitation of boride inside Fe matrix, and it features outstanding hardness and wear resistance properties. However, Fe-Cr-B alloy is a difficult material to process, making it difficult to use as a bulk type structure material which requires delicate shapes. This study attempted to manufacture Fe-Cr-B alloy using a 3D printing process, laser metal deposition. This study also investigated the microstructure, hardness and compression properties of the manufactured alloy. Phase analysis results is confirmed that α-Fe phase as matrix and (Cr, Fe)2B phase as reinforcement phase. In the case of (Cr, Fe)2B phase, differences were observed according to the sample location. While long, coarse, unidirectional needle-type boride phases (~11 μm thickness) were observed in the center area of the sample, relatively finer boride phases (~6 μm thickness) in random directions were observed in other areas. At room temperature compression test results confirmed that the sample had a compression strength is approximately 2.1 GPa, proving that the sample is a material with extremely high strength. Observation of the compression fracture surface identified intergranular fractures in areas with needle-type boride, and transgranular fractures in areas with random borides. Based on this results, this study also reviewed the deformation behavior of LMD Fe-Cr-B alloy in relation to its microstructures.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1459-1462
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Strut Thickness on Room and High Temperature Compressive Properties of Block-Type Ni-Cr-Al Powder Porous Metals
Autorzy:
Kang, B.-H.
Park, M.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/355591.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ni-Cr-Al
powder porous metal
strut thickness
high temperature
compressive behavior
Opis:
This study investigated the effect of strut thickness on the room and high temperature compressive properties of block-type Ni-Cr-Al powder porous metals with ~3000 μm pore size manufactured using a new powder process. Two block-type Ni-Cr-Al porous metals with different strut thicknesses were manufactured. The strut thicknesses of two block foams were 340 μm (A) and 383 μm (B), respectively. Room temperature, 500°C, 650°C and 800°C compressive tests were performed. The compressive results identified typical elastic, plateau and densification regions of foam material in all temperature conditions. Regardless of the strut thickness, compressive strength (maximum peak stress) decreased as deformation temperature increased. In all deformation temperature ranges, the compressive strength measured higher in the porous metal with greater strut thickness (B). The high temperature deformation behavior of powder porous metal was confirmed to be affected by the structural factor and microstructural factor of the porous metal. With the findings described above, this study also discussed the high temperature deformation mechanism of the Ni-Cr-Al metal foam based on fracture surfaces after the high temperature compressions.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1329-1334
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Surfactant Addition on Bi2Te3 Nanostructures Synthesized by Hydrothermal Method
Autorzy:
Dharmaiah, P.
Lee, C. H.
Madavali, B.
Hong, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/351609.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
bismuth telluride
hydrothermal synthesis
spark plasma sintering
thermoelectric materials
X-ray diffraction
Opis:
In the present work, we have prepared Bi2Te3 nanostructures with different morphologies such as nano-spherical, nanoplates and nanoflakes obtained using various surfactant additions (EG, PVP, and EDTA) by a hydrothermal method. The shape of the nanoparticles can be controlled by addition of surfactants. The samples were characterized by x-ray diffraction (XRD) and scanning electron microscopy (SEM). It is found that the minority BiOCl phase disappears after maintained pH at 10 with EG as surfactant. SEM bulk microstructure reveals that the sample consists of fine and coarse grains. Temperature dependence of thermoelectric properties of the nanostructured bulk sample was investigated in the range of 300-450K. The presence of nanograins in the bulk sample exhibits a reduction of thermal conductivity and less effect on electrical conductivity. As a result, a figure of merit of the sintered bulk sample reached 0.2 at 400 K. A maximum micro Vickers hardness of 102 Hv was obtained for the nanostructured sample, which was higher than the other reported results.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1005-1010
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Warm Tensile Deformation Behavior and Constitutive Equation of Supersaturated Solid-Solutionized Al-9Mg Extruded Alloy
Autorzy:
Yang, Seung Y.
Kim, Bong H.
Lee, Da B.
Choi, Kweon H.
Kim, Nam S.
Ha, Seong H.
Yoon, Young O.
Lim, Hyun K.
Kim, Shae
Kim, Young J.
Powiązania:
https://bibliotekanauki.pl/articles/2048882.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum alloy
Al-9Mg alloy
tensile test
constitutive equation
Opis:
In this paper, as a purpose to apply the supersaturated solid-solutionized Al-9Mg alloy to the structural sheet parts of automotive, tensile tests were conducted under the various conditions and a constitutive equation was derived from the tensile test results. Al-9Mg alloy was produced using a special Mg master alloy containing Al2Ca during the casting process and extruded into the sheet. In order to study the deformation behavior of Al-9Mg alloy in warm temperature forming environments, tensile tests were conducted under the temperature of 373 K-573 K and the strain rate of 0.001/s~0.1/s. in addition, by using the raw data obtained from tensile tests, a constitutive equation of the Al-9Mg alloy was derived for predicting the optimized condition of the hot stamping process. Al-9Mg alloy showed uncommon deformation behavior at the 373 K and 473 K temperature conditions. The calculated curves from the constitutive equation well-matched with the measured curves from the experiments particularly under the low temperature and high strain rate conditions.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 1013-1018
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect Of DyMn Alloy-Powder Addition On Microstructure And Magnetic Properties Of NdFeB Sintered Magnets
Wpływ dodatku proszku DyMn na mikrostrukturę i właściwości magnetyczne spiekanych magnesów NdFeB
Autorzy:
Lee, M.-W.
Dhakal, D. R.
Kim, T. H.
Lee, S. R.
Kim, H. J.
Jang, T. S.
Powiązania:
https://bibliotekanauki.pl/articles/357010.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nd-Fe-B sintered magnets
DyMn-alloy powder
coercivity
low melting point element
magnesy spiekane
proszek DyMn
koercja
elementy o niskiej temperaturze topnienia
Opis:
Micostructural change and corresponding effect on coercivity of a NdFeB sintered magnet mixed with small amount of DyMn powder was investigated. In the sintered magnet mixed with the DyMn alloy-powder Dy-rich shell was formed at outer layer of the main grains, while Mn was mostly concentrated at Nd-rich triple junction phase (TJP), lowering melting temperature of the Nd-rich phase that eventually improved the microstructural characteristics of the gain boundary phase. The coercivity of a magnet increased more than 3.5 kOe by the mixing of the DyMn alloy-powder.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1407-1409
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Mechanical Properties of Hot-deformed AlMg4 Alloys with the Variations of Mn, Fe, and Si Contents
Autorzy:
Lee, Da B.
Kim, Bong H.
Choi, Kweon H.
Yang, Seung Y.
Kim, Nam S.
Ha, Seong H.
Yoon, Young O.
Lim, Hyun K.
Kim, Shae
Hyun, Soong K..
Powiązania:
https://bibliotekanauki.pl/articles/351603.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-Mg alloy
intermetallic compounds
homogenization
hot-rolling
microstructure
Opis:
This paper aims to investigate the microstructural evolution and mechanical properties of hot-deformed AlMg4 alloys with Mn, Fe, and Si as the main impurities. For this purpose, solidification behavior and microstructural evolution during hot-rolling and heat-treatment processes are investigated by using theoretical calculations and experimental characterization. The crystallization and morphological transformation of intermetallic Al3 Fe, Al6 Mn, and Mg2 Si phases are revealed and discussed in terms of the variation in chemical composition. Following a homogenization heat-treatment, the effect of heat treatment on the intermetallic compounds is also investigated after hot-rolling. It was revealed that the Mg2 Si phase can be broken into small particles and spherodized more easily than the Al3 Fe intermetallic phase during the hot-rolling process. For the Mn containing alloys, both yield and ultimate tensile strength of the hot-rolled alloys increased from 270 to 296 MPa while elongation decreased from 17 to 13%, which can be attributed to Mn-containing intermetallic as well as dispersoid.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1255-1259
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermal Conductivity and Microstructure of Copper Coated Graphite Composite by Spark Plasma Sintering Process
Autorzy:
Park, S. H.
Kim, D. B.
Lee, R. G.
Son, I. J.
Powiązania:
https://bibliotekanauki.pl/articles/355632.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metal matrix composites
thermal conductivity
thermal expansion
interfacial bonding
spark plasma sintering
Opis:
This study focuses on the fabrication of thermal management material for power electronics applications using graphite flake reinforced copper composites. The manufacturing route involved electroless plating of copper in the graphite flake and sintering process are optimized. The microstructures, interface, thermal properties, and relative density of graphite/Cu composites are investigated. The relative density of the composites shows 99.5% after sintering. Thermal conductivities and coefficients of thermal expansion of this composites were 400-480 Wm-1K-1 and 8 to 5 ppm k-1, respectively. Obtained graphite nanoplatelets-reinforced composites exhibit excellent thermo-physical properties to meet the heat dispersion and matching requirements of power electronic devices to the packaging materials.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1303-1306
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reaction Kinetics and Morphological Study of TiNb2O7 Synthesized by Solid-State Reaction
Autorzy:
Choi, S. H.
Ali, B.
Choi, K. S.
Hyun, S. K.
Sim, J. J.
Choi, W. J.
Joo, W.
Lim, J. H.
Lee, T. H.
Kim, T. S.
Park, K. T.
Powiązania:
https://bibliotekanauki.pl/articles/355326.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solid state reaction
kinetic analysis
quantitative phase analysis
TiNb2O7 synthesis
Opis:
Although TiNb2O7 is regarded as a material with high application potential in lithium-ion batteries (LIBs) and solid-oxide fuel cells (SOFCs), it has been difficult to find suitable cost-effective conditions for synthesizing it on a commercial scale. In this study, TiNb2O7 compounds were synthesized by a solid state synthesis process. For stoichiometrically precise synthesis of the TiNb2O7 phase, the starting materials, TiO2 and Nb2O5 were taken in a 1:1 molar ratio. Activation energy and reaction kinetics of the system were investigated at various synthesis temperatures (800,1000,1200, and 1400°C) and for various holding durations (1,5,10, and 20 h). Furthermore, change in the product morphology and particle size distribution were also evaluated as a function of synthesis temperature and duration. Additionally, quantitative phase analysis was conducted using the Rietveld refinement method. It was found that increases in the synthesis temperature and holding time lead to increase in the mean particle size from 1 to 4.5 μm. The reaction rate constant for the synthesis reaction was also calculated.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1051-1056
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies on the effect of coal particle size on biodepyritization of high sulfur coal in batch bioreactor
Autorzy:
Singh, S.
Srichandan, H.
Pathak, A.
Gahan, Ch. S.
Lee, S.
Kim, D. J.
Kim, B. G.
Powiązania:
https://bibliotekanauki.pl/articles/778523.pdf
Data publikacji:
2015
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
biodepyritization
coal
pyrite
stirred tank bioreactor
Opis:
The moderate thermophilic mix culture bacteria were used to depyritize the Illinois coal of varying particle sizes (-100 μm, 100-200 μm, +200 μm). Mineral libration analysis showed the presence of pyrite along with other minerals in coal. Microbial depyritization of coal was carried out in stirred tank batch reactors in presence of an iron-free 9K medium. The results indicate that microbial depyritization of coal using moderate thermophiles is an efficient process. Moreover, particle size of coal is an important parameter which affects the efficiency of microbial depyritization process. At the end of the experiment, a maximum of 75% pyrite and 66% of pyritic sulphur were removed from the median particle size. The XRD analysis showed the absence of pyrite mineral in the treated coal sample. A good mass balance was also obtained with net loss of mass ranging from 5-9% showing the feasibility of the process for large scale applications.
Źródło:
Polish Journal of Chemical Technology; 2015, 17, 1; 97-102
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Double Step Sintering Behavior Of 316L Nanoparticle Dispersed Micro-Sphere Powder
Dwuetapowe spiekanie mikrosferycznych nanocząstek proszku 316L
Autorzy:
Jeon, B.
Sohn, S. H.
Lee, W.
Han, C.
Kim, Y. D.
Choi, H.
Powiązania:
https://bibliotekanauki.pl/articles/355221.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
316L stainless steel
nanoparticle dispersed micro-sphere
pulse wire explosion
sintering
stal nierdzewna 316L
spiekanie dwuetapowe
mikrosferyczne nanocząstki
Opis:
316L stainless steel is a well-established engineering material and lots of components are fabricated by either ingot metallurgy or powder metallurgy. From the viewpoints of material properties and process versatility, powder metallurgy has been widely applied in industries. Generally, stainless steel powders are prepared by atomization processes and powder characteristics, compaction ability, and sinterability are quite different according to the powder preparation process. In the present study, a nanoparticle dispersed micro-sphere powder is synthesized by pulse wire explosion of 316L stainless steel wire in order to facilitate compaction ability and sintering ability. Nanoparticles which are deposited on the surface of micro-powder are advantageous for a rigid die compaction while spherical micro-powder is not to be compacted. Additionally, double step sintering behavior is observed for the powder in the dilatometry of cylindrical compact body. Earlier shrinkage peak comes from the sintering of nanoparticle and later one results from the micro-powder sintering. Microstructure as well as phase composition of the sintered body is investigated.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1155-1158
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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