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Wyszukujesz frazę "Lee, K. J." wg kryterium: Autor


Tytuł:
Properties of Copper Doped Neodymium Nickelate Oxide as Cathode Material for Solid Oxide Fuel Cells
Autorzy:
Lee, K. J.
Choe, Y-J.
Hwang, H-J.
Powiązania:
https://bibliotekanauki.pl/articles/351292.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solid oxide fuel cells
copper
electrical conductivity
excess oxygen
Opis:
Mixed ionic and electronic conducting K2NiF4-type oxide, Nd2Ni1-xCuxO4+δ (x=0~1) powders were synthesized by solid state reaction technique and solid oxide fuel cells consisting of a Nd2Ni1-xCuxO4+δ cathode, a Ni-YSZ anode and ScSZ as an electrolyte were fabricated. The effect of copper substitution for nickel on the electrical and electrochemical properties was examined. Small amount of copper doping (x=0.2) resulted in the increased electrical conductivity and decreased polarization resistance. It appears that this phenomenon was associated with the high mean valence of nickel and copper and the resulting excess oxygen (δ). It was found that power densities of the cell with the Nd2Ni1-xCuxO4+δ (x=0.1 and 0.2) cathode were higher than that of the cell with theNd2NiO4+δ cathode.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 625-628
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cr Poisoning On Nd2Ni0.95Cu0.05O4+δ Cathode for Solid Oxide Fuel Cells
Autorzy:
Choe, Y-J.
Lee, K. J.
Hwang, H-J.
Powiązania:
https://bibliotekanauki.pl/articles/354728.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chromium poisoning
Ruddlesden-Popper
layered perovskite
solid oxide fuel cells
Nd2NiO4
Opis:
In this study, Nd2Ni1-xCuxO4+δ (x=0, 0.05, 0.1, and 0.2) layered perovskite powders were synthesized by the glycine nitrate process (GNP) and the chromium poisoning effect on the electrochemical performance of the Nd2Ni0.95Cu0.05O4+δ and La0.6Sr0.4Co0.2Fe0.88O3-δ cathodes were investigated. In the case of the LSCF cathode, the strontium chromite phase formed after the exposure of the gaseous chromium species, while there was no additional phase in the Nd2Ni0.95Cu0.05O4+δ cathode. The area specific resistance (ASR) of the Nd2Ni0.95Cu0.05O4+δ cathode did not change significantly after the exposure of the gaseous chromium species at 800°C
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 629-634
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Aluminum Oxide Formation On Fecral Catalyst Support By Electro-Chemical Coating
Powstawanie tlenku glinu na nośniku katalizatora FeCrAl przez osadzanie elektrochemiczne
Autorzy:
Yang, H. S.
Jang, D. H.
Lee, K. J.
Powiązania:
https://bibliotekanauki.pl/articles/355942.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FeCrAl
catalyst support
aluminum oxide formation
PEO
plasma electrolytic oxidation
electrochemical coating
nośnik katalizatora
tlenek glinu
plazmowe utlenianie elektrolityczne
elektrochemiczne osadzanie
Opis:
FeCrAl is comprised essentially of Fe, Cr, Al and generally considered as metallic substrates for catalyst support because of its advantage in the high-temperature corrosion resistance, high mechanical strength, and ductility. Oxidation film and its adhesion on FeCrAl surface with aluminum are important for catalyst life. Therefore various appropriate surface treatments such as thermal oxidation, Sol, PVD, CVD has studied. In this research, PEO (plasma electrolytic oxidation) process was applied to form the aluminum oxide on FeCrAl surface, and the formed oxide particle according to process conditions such as electric energy and oxidation time were investigated. Microstructure and aluminum oxide particle on FeCrAl surface after PEO process was observed by FE-SEM and EDS with element mapping analysis. The study presents possibility of aluminum oxide formation by electro-chemical coating process without any pretreatment of FeCrAl.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1503-1506
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hearing impairment among Korean farmers, based on a 3-year audiometry examination
Autorzy:
Lee, S.
Lee, K.
Lee, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/2082988.pdf
Data publikacji:
2019
Wydawca:
Instytut Medycyny Wsi
Tematy:
agriculture
sensorineural hearing loss
audiometry
Opis:
Introduction and objective. Work noise exposure among farmers can cause hearing loss. Farmers are exposed to hazardous noise from equipment and domestic animals, and experience high rates of noise-induced hearing loss. The aim of our study was to evaluate the hearing thresholds of farmers in Korea. This study is the first to evaluate hearing impairment in Korean farmers nationwide. There have been few studies that have performed audiometric testing to measure hearing impairment at the national level in Korea. Materials and method. Through the Farm Work Safety Model Project among the 40 villages in which inhabitants received health check-ups from 2006–2008, 2,027 people from 35 villages were targeted (957 people in 16 villages in 2006, 436 people in five villages in 2007, and 634 people in 14 villages in 2008) and underwent pure tone audiometry tests. 2,027 people from 35 villages underwent pure tone audiometry tests through the Farm Work Safety Model Project. The tests were conducted using a portable audiometer, and air conduction thresholds were determined. Results. Hearing impairment at 3kHz and above was more prevalent in men than in women. The prevalence of moderate- to-profound hearing impairment was 19.6% in the total study population and increased with age. Conclusions. It is proposed that the high prevalence rate of farmers’ hearing impairment may be due to excessive workplace noise. To manage farmers’ hearing health, precise evaluations of farmers’ hearing acuity and noise exposure on farms should be conducted. This study might be a stepping-stone to protect farmers’ hearing health.
Źródło:
Annals of Agricultural and Environmental Medicine; 2019, 26, 1; 148-153
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rapid Synthesis of Gold Nano-Particles Using Pulse Waved Potential in a Non-Aqueous Electrolyte
Autorzy:
Jang, J. G.
Lee, J.-O.
Lee, C. K.
Powiązania:
https://bibliotekanauki.pl/articles/352529.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gold
nanoparticle
nonaqueous electrolyte
pulse wave
catalyst
Opis:
Rapid synthesis of gold nanoparticles (AuNPs) by pulsed electrodeposition was investigated in the non-aqueous electrolyte, 1-ethyl-3-methyl-imidazoliumbis(trifluoro- methanesulfonyl)imide ([EMIM]TFSI) with gold trichloride (AuCl3). To aid the dissolution of AuCl3, 1-ethyl-3-methyl-imidazolium chloride ([EMIM]Cl) was used as a supporting electrolyte in [EMIM]TFSI. Cyclicvoltammetry experiments revealed a cathodic reaction corresponding to the reduction of gold at −0.4 V vs. Pt-QRE. To confirmthe electrodeposition process, potentiostatic electrodeposition of gold in the non-aqueous electrolyte was conducted at −0.4 V for 1 h at room temperature. To synthesize AuNPs, pulsed electrodeposition was conducted with controlled duty factor, pulse duration, and overpotential. The composition, particle-size distribution, and morphology of the AuNPs were confirmed by field-emission scanning electron microscopy (FE-SEM), energy-dispersive spectroscopy (EDS), and transmission electron microscopy (TEM). The electrodeposited AuNPs were uniformly distributed on the platinum electrode surface without any impurities arising from the non-aqueous electrolyte. The size distribution of AuNPs could be also controlled by the electrodeposition conditions.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1389-1392
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Compressive Deformation Behavior of Thick Micro-Alloyed HSLA Steel Plates at Elevated Temperatures
Autorzy:
Lee, J.-H.
Kim, D.-O.
Lee, K.
Powiązania:
https://bibliotekanauki.pl/articles/351774.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
alloys
rolling
strain rate
compression test
HSLA steel
Opis:
The hot deformation behavior of a heavy micro-alloyed high-strength low-alloy (HSLA) steel plate was studied by performing compression tests at elevated temperatures. The hot compression tests were carried out at temperatures from 923 K to 1,223 K with strain rates of 0.002 s-1 and 1.0 s-1. A long plateau region appeared for the 0.002 s-1 strain rate, and this was found to be an effect of the balancing between softening and hardening during deformation. For the 1.0 s-1 strain rate, the flow stress gradually increased after the yield point. The temperature and the strain rate-dependent parameters, such as the strain hardening coefficient (n), strength constant (K), and activation energy (Q), obtained from the flow stress curves were applied to the power law of plastic deformation. The constitutive model for flow stress can be expressed as σ = (39.8 ln (Z) – 716.6) · ε(−0.00955ln(Z) + 0.4930) for the 1.0 s-1 strain rate and σ = (19.9ln (Z) – 592.3) · ε(−0.00212ln(Z) + 0.1540) for the 0.002 s-1 strain rate.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1191-1196
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Pre-Sintering on the Diffusion Treatment of HRE for Coercivity Enhancement of a NdFeB Sintered Magnet
Autorzy:
Lee, M. W.
Lee, J. K.
Jang, T. S.
Powiązania:
https://bibliotekanauki.pl/articles/355250.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grain boundary diffusion process
GBDP
NdFeB magnet
coercivity
pre-sintering
Opis:
We investigated the effect of pre-sintering process on the penetration behavior of Dy in a NdFeB sintered magnet which was grain boundary diffusion treated with Cu/Al mixed Dy source. The pre-sintering of a magnet was performed at 900°C in vacuum and then the pre-sintered body was dipped in the solutions of DyH2, DyH2 + Cu, and DyH2 + Al, respectively. The dipped pre-sintered body were then fully sintered 4 hours at 1060°C followed by a subsequent annealing. The pre-sintering apparently improved the diffusivity of Dy atoms. The penetration of Dy into the magnet extended almost to 2,000 μm from the surface, about four times deeper than that of the normally sintered and diffusion treated one, when the DyH2 + Al solution was used as a Dy source. However, the resulting increase of coercivity was about 4 kOe, somewhat lower than that of the normally treated one, mostly due to excessive oxide formation that hindered to make a continuous Nd-rich grain boundary phase and a core-shell type structure.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 597-601
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study On Dispersion Stability Of Nickel Nanoparticles Synthesized By Wire Explosion In Liquid Media
Badanie stabilności dyspersji nanocząstek niklu wytworzonych metodą WEP w ciekłym medium
Autorzy:
Kim, C. K.
Lee, G.-J.
Lee, M. K.
Rhee, C. K.
Powiązania:
https://bibliotekanauki.pl/articles/356909.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nickel nanofluid
pulsed wire evaporation
surfactant
zeta potential
dispersion stability
nanocząstka niklu
środek powierzchniowo czynny
stabilność dyspersji
potencjał zeta
dyspersja
Opis:
In this study, nickel nanoparticles were synthesized in ethanol using portable pulsed wire evaporation, which is a one-step physical method. From transmission electron microscopy images, it was found that the Ni nanoparticles exhibited a spherical shape with an average diameter of 7.3 nm. To prevent aggregation of the nickel nanoparticles, a polymer surfactant was added into the ethanol before the synthesis of nickel nanoparticles, and adsorbed on the freshly synthesized nickel nanoparticles during the wire explosion. The dispersion stability of the prepared nickel nanofluids was investigated by zeta-potential analyzer and Turbiscan optical analyzer. As a result, the optimum concentration of polymer surfactant to be added was suggested for the maximized dispersion stability of the nickel nanofluids.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1379-1382
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of PVA Polymer Type and Calcination Temperature on Synthesis of Nanocrystalline Yttria Powder by Polymer Solution Route
Autorzy:
Yang, Y.-K.
Lee, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/356024.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
yttria
PVA
nanocrystalline
synthesis
nanowire
Opis:
Nano-sized yttria (Y2O3) powders were synthesized by a polymer solution route using polyvinyl alcohol (PVA) as an organic carrier. The PVA polymer affected the dispersion of yttrium ions in precursor sol. In this study, three kinds of PVA polymer (different molecular weight) were applied for synthesis of yttria powder. The PVA type as well as calcination temperature had a strongly influence on the particle morphology. Single crystal nano wire particles were observed at the temperature of polymer burn out range and the size was dependent on the PVA type. The stable, fully crystallized yttria powder was obtained through the calcination at 800°C for 1 h. The yttria powder prepared with the high weight PVA (MW: 153,000) revealed a particle size of 30 nm with a surface area of 18.8 m2/g.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1473-1476
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Crystallization Behavior of Zr62Al8Ni13Cu17 Metallic Glass
Autorzy:
Jo, M. S.
Lee, J. K.
Powiązania:
https://bibliotekanauki.pl/articles/353070.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metallic glass
crystallization
kinetics
amorphous
Zr-based
Opis:
The crystallization behavior has been studied in Zr62Al8Ni13Cu17 metallic glass alloy. The Zr62Al8Ni13Cu17 metallic glass crystallized through two steps. The fcc Zr2Ni phase transformed from the amorphous matrix during first crystallization and then the Zr2Ni and residual amorphous matrix transformed into a mixture of tetragonal Zr2Cu and hexagonal Zr6Al2Ni phases. Johnson- Mehl-Avrami analysis of isothermal transformation data suggested that the formation of crystalline phase is primary crystallization by diffusion-controlled growth.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1023-1026
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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