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Wyszukujesz frazę "Kim, Jung-Hyun" wg kryterium: Autor


Wyświetlanie 1-7 z 7
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
Artykuł
Tytuł:
OPPORTUNITIES IN TECHNOLOGY-ENHANCED LANGUAGE LEARNING (TELL) CLASSROOM ENVIRONMENTS
Autorzy:
Jung, Hee-Jung
Kim, Sang Hyun
Powiązania:
https://bibliotekanauki.pl/articles/569512.pdf
Data publikacji:
2004
Wydawca:
Uniwersytet Marii Curie-Skłodowskiej w Lublinie. IATEFL Poland Computer Special Interest Group
Źródło:
Teaching English with Technology; 2004, 4, 4
1642-1027
Pojawia się w:
Teaching English with Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Si Addition on Microstructure and Mechanical Properties of the Al Alloys with High Cr Content Prepared by Gas Atomization and SPS Processes
Autorzy:
Kim, Yong-Ho
Oh, Ik-Hyun
Yoo, Hyo-Sang
Park, Hyun-Kuk
Lee, Jung-Han
Son, Hyeon-Taek
Powiązania:
https://bibliotekanauki.pl/articles/354961.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-Cr-Si
gas atomization
spark plasma sintering
powder
rapid solidification
Opis:
This research describes effects of Si addition on microstructure and mechanical properties of the Al-Cr based alloys prepared manufactured using gas atomization and SPS (Spark Plasma Sintering) processes. The Al-Cr-Si bulks with high Cr and Si content were produced successfully using SPS sintering process without crack and obtained fully dense specimens close to nearly 100% T. D. (Theoretical Density). Microstructure of the as-atomized Al-Cr-Si alloys with high contents of Cr and Si was composed multi-phases with hard and thermally stable such as Al13Cr4Si4, AlCrSi, Al8Cr5 and Cr3Si intermetallic compounds. The average hardness values were 703 Hv for S5, 698 Hv for S10 and 824 Hv for S20 alloy. Enhancement of hardness value was resulted from the formation of the multi-intermetallic compound with hard and thermally stable and fine microstructure by the addition of high Cr and Si using rapid solidification and SPS process.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 3; 1045-1049
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and performance of dual-band MWIR/LWIR focal plane arrays based on a type-II superlattice nBn structure
Autorzy:
Lee, Hyun-Jin
Eom, Jun Ho
Jung, Hyun Chul
Kang, Ko-Ku
Ryu, Seong Min
Jang, Ahreum
Kim, Jong Gi
Kim, Young Ho
Jung, Han
Kim, Sun Ho
Choi, Jong Hwa
Powiązania:
https://bibliotekanauki.pl/articles/2204217.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
InAs/GaSb type-II superlattice
dualband detector
dark current
spectral quantum efficiency
noise equivalent temperature difference
Opis:
Dual-band infrared detector, which acquires more image information than single-band detectors, has excellent detection, recognition, and identification capabilities. The dual-band detector can have two bumps to connect with each absorber layer, but it is difficult to implement small pitch focal plane arrays and its fabrication process is complicated. Therefore, the most effective way for a dual-band detector is to acquire each band by biasselectable with one bump. To aim this, a dual-band MWIR/LWIR detector based on an InAs/GaSb type-II superlattice nBn structure was designed and its performance was evaluated in this work. Since two absorber layers were separated by the barrier layer, each band can be detected by bias-selectable with one bump. The fabricated dual-band device exhibited the dark current and spectral response characteristics of MWIR and LWIR bands under negative and positive bias, respectively. Spectral crosstalk that is a major issue in dualband detectors was also improved. Finally, a 20 µm pitch 640 x 512 dual-band detector was fabricated, and both MWIR and LWIR images exhibited an average noise equivalent temperature difference of 30 mK or less at 80 K.
Źródło:
Opto-Electronics Review; 2023, 31, Special Issue; art. no. e144560
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of Nickel Nanoparticles Using Nickel Raffinate Separated by Solvent Extraction from The Spent FeCl3 Etching Solution
Autorzy:
Park, Il-Jeong
Swain, Basudev
Kim, Dae-Weon
Kim, Geon-Hong
Han, Deok-Hyun
Jung, Hang-Chul
Powiązania:
https://bibliotekanauki.pl/articles/354453.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nickel
recycling
solvent extraction
chemical reduction
Opis:
FeCl3 bearing etching solution is mainly used for etching of metals used in shadow masks, PCBs and so on. Due course of Invar alloy etching process the FeCl3 bearing etching solution get contaminated with Ni2+ which affect adversely the etching efficiency. Hence, FeCl3 bearing etching solution discarded after several cycle of operation causes an environmental and economic problem. To address both the issues the etching solution was purified through solvent extraction and remained Ni2+ recovered by wet chemical reduction using hydrazine. For optimum Fe3+ extraction efficiency, various extraction parameter were optimized and size and morphology of the recovered pure Ni powder was analyzed. The reported process is a simple process to purify and recover Ni from industry etching solution.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 531-534
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Surface Treatments on Cast-Bonding Characteristics of Steel-Aluminum Hybrid Composite Materials
Autorzy:
Kim, Hyo-Jung
Kim, Tae Hyeong
Shin, Je Sik
Park, Seung Yeon
Hyun, Soongkeun
Lim, Kyoung Mook
Powiązania:
https://bibliotekanauki.pl/articles/353007.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cast-bonding
aluminum
steel sheet
composite material
bonding surface
Opis:
In this study, we investigated the bonding mechanism of surface-treated steel with an Al-Si alloy in order to produce steel-aluminum (STL-Al) hybrid composite materials by cast-bonding. The results showed that there are differences in the phase and properties of the hybrid composite materials bonded specimens depending on the surface treatment of the steel sheet used, and that the bonding conditions can be controlled further by detailed conditions of the surface treatment. Based on the interfacial bonding strengths measured here, the galvanized surface treatment induced metallurgical bonding to form a reaction layer on the bonding surface and was determined to be the most effective surface treatment.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 889-892
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 1-7 z 7

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