Autor: Kim, E.-B. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Effect of Ga2O3 Nanoparticles Dispersion on Microstructure and Thermoelectric Properties of p-Type BiSbTe Based Alloys
Autorzy:: Kim, E.-B.
Koo, J.-M.
Hong, S.-J.
Powiązania:: https://bibliotekanauki.pl/articles/351366.pdf
Data publikacji:: 2017
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: thermoelectric properties
Bi0.5Sb1.5Te3 alloys
Seebeck coefficient
mechanical alloying
spark plasma sintering
Opis:: In this study, p-type Bi_0.5Sb_1.5Te₃ based nanocomposites with addition of different weight percentages of Ga₂O₃ nanoparticles are fabricated by mechanical milling and spark plasma sintering. The fracture surfaces of all Bi_0.5Sb_1.5Te₃ nanocomposites exhibited similar grain distribution on the entire fracture surface. The Vickers hardness is improved for the Bi_0.5Sb_1.5Te₃ nanocomposites with 6 wt% added Ga₂O₃ due to exhibiting fine microstructure, and dispersion strengthening mechanism. The Seebeck coefficient of Bi_0.5Sb_1.5Te₃ nanocomposites are significantly improved owing to the decrease in carrier concentration. The electrical conductivity is decreased rapidly upon the addition of Ga₂O₃ nanoparticle due to increasing carrier scattering at newly formed interfaces. The peak power factor of 3.24 W/mK² is achieved for the base Bi_0.5Sb_1.5Te₃ sintered bulk. TheBi_0.5Sb_1.5Te₃ nanocomposites show low power factor than base sample due to low electrical conductivity.
Źródło:: Archives of Metallurgy and Materials; 2017, 62, 2B; 993-997
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

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

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Skocz do pozycji: 3.

Tytuł:: Pressure drop of filtering facepiece respirators: How low should we go?
Autorzy:: Kim, Jung-Hyun
Roberge, Raymond J.
Powell, Jeffrey B.
Shaffer, Ronald E.
Ylitalo, Caroline M.
Sebastian, John M.
Powiązania:: https://bibliotekanauki.pl/articles/2177016.pdf
Data publikacji:: 2015-02-24
Wydawca:: Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:: respirator
filter
oral breathing
nasal breathing
Opis:: Introduction This study was undertaken to determine the mean peak filter resistance to airflow (R filter) encountered by subjects while wearing prototype filtering facepiece respirators (PRs) with low Rfilter during nasal and oral breathing at sedentary and low-moderate work rates. Material and methods In-line pressure transducer measurements of mean R filter across PRs with nominal R filter of 29.4 Pa, 58.8 Pa and 88.2 Pa (measured at 85 l/min constant airflow) were obtained during nasal and oral breathing at sedentary and low-moderate work rates for 10 subjects. Results The mean R filter for the 29.4 PR was significantly lower than the other 2 PRs (p < 0.000), but there were no significant differences in mean R filter between the PRs with 58.8 and 88.2 Pa filter resistance (p > 0.05). The mean R filter was greater for oral versus nasal breathing and for exercise compared to sedentary activity (p < 0.001). Conclusions Mean oral and nasal R filter for all 3 PRs was at, or below, the minimal threshold level for detection of inspiratory resistance (the 58.8–74.5 Pa/l×s⁻¹), which may account for the previously-reported lack of significant subjective or physiological differences when wearing PRs with these low R filter. Lowering filtering facepiece respirator R filter below 88.2 Pa (measured at 85 l/min constant airflow) may not result in additional subjective or physiological benefit to the wearer.
Źródło:: International Journal of Occupational Medicine and Environmental Health; 2015, 28, 1; 71-80
1232-1087
1896-494X
Pojawia się w:: International Journal of Occupational Medicine and Environmental Health
Dostawca treści:: Biblioteka Nauki