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Wyszukujesz frazę "Min, Kim" wg kryterium: Autor


Tytuł:
Theoretical investigations into the Spectrophotometrically Analyzed Niobium (V)-6-Chloro-3-hydroxy-7-methyl-2-(2’-thienyl)-4H-chromen-4-one Complex
Autorzy:
Dhonchak, Chetna
Agnihotri, Nivedita
Azam, Mohammad
Javed, Saleem
Muthu, Sambantham
Al-Resayes, Saud I.
Min, Kim
Powiązania:
https://bibliotekanauki.pl/articles/27315655.pdf
Data publikacji:
2023
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Niobium
6-Chloro-3-hydroxy-7-methyl-2-(2’-thienyl)-4H-chromen-4-one
spectrophotometry
DFT
density functional theory
MEP
molecular electrostatic potential
Opis:
Pentavalent niobium cation forms a stable yellow-colored binary complex with 6-chloro-3-hydroxy-7-methyl-2-(2’- thienyl)-4H-chromen-4-one (CHMTC) in the ratio of 1:2. The complex is quantitatively extractable into carbon tetrachloride from HClO4 solution maintained at pH 1.26–1.75 and strictly adheres to Beer’s law as verified by the Ringbom plot with an optimized range of determination as 0.385–1.211 ppm of Nb(V). The ligand-metal complex system shows good precision, accuracy, sensitivity, and selectivity and handles satisfactorily the analysis of several samples of varying complexity. The results are highly reproducible as confirmed by statistical data. The stability of the complex is theoretically confirmed with the help of HOMO-LUMO values and the energy gap [for CHMTC, ΔEgap = 3.62 V and for Nb(V)-CHMTC Complex, ΔEgap = 2.97 eV]. The reactivity descriptors were calculated for detailed computational study to probe into the chemical behavior of the studied ligand and its complex. Further, mapped electrostatic potential diagrams help in justifying the donor sites of CHMTC ligand which is in accordance with the analytical findings.
Źródło:
Polish Journal of Chemical Technology; 2023, 25, 3; 63--70
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of a chemical risk assessment method of South Korea for chemicals classified as carcinogenic, mutagenic or reprotoxic (CMR)
Autorzy:
Kim, Min-Uk
Byeon, Sang-Hoon
Powiązania:
https://bibliotekanauki.pl/articles/2162005.pdf
Data publikacji:
2018-07-04
Wydawca:
Instytut Medycyny Pracy im. prof. dra Jerzego Nofera w Łodzi
Tematy:
exposure
hazard
risk assessment
occupational
work environment
chemical hazard
Opis:
Objectives Chemicals were used in various fields by the development of industry and science and technology. The Chemical Hazard Risk Management (CHARM) was developed to assess the risk of chemicals in South Korea. In this study, we were to evaluate the CHARM model developed for the effective management of workplace chemicals. Material and Methods We used 59 carcinogenic, mutagenic or reprotoxic (CMR) materials, which are both the work environment measurement result and the usage information among the manufacturer data. The CHARM model determines the risk to human health using the exposure level (based on working environment measurements or a combination of the quantity used and chemical physical properties (e.g., fugacity and volatility)), hazard (using occupational exposure limit (OEL) or Risk phrases (R-phrases)/Hazard statements (H-statements) from the Material Safety Data Sheet (MSDS)). Results The risk level was lower when using the results of the work environment measurement than when applying the chemical quantity and physical properties in the exposure level evaluation method. It was evaluated as grade 4 for the CMR material in the hazard class determination. The risk assessment method by R-phrases was evaluated more conservatively than the risk assessment method by OEL. And the risk assessment method by H-statements was evaluated more conservatively than the risk assessment method by R-phrases. Conclusions The CHARM model was gradually conservatively assessed as it proceeded in the next step without quantitative information for individual workplaces. The CHARM is expected to help identify the risk if the hazards and exposure levels of chemicals were identified in individual workplaces. For CMR substances, although CHARM is highly evaluated for hazards, the risk is assessed to be low if exposure levels are assessed low. When evaluating the risk of highly hazardous chemicals such as CMR substances, we believe the model should be adapted to be more conservative and classify these as higher risk. Int J Occup Med Environ Health 2018;31(4):491–501
Źródło:
International Journal of Occupational Medicine and Environmental Health; 2018, 31, 4; 491-501
1232-1087
1896-494X
Pojawia się w:
International Journal of Occupational Medicine and Environmental Health
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effect of Peer Tutoring for College Students: Who Benefits More from Peer Tutoring, Tutors or Tutees?
Autorzy:
Seo, Eun Hee
Kim, Min Ji
Powiązania:
https://bibliotekanauki.pl/articles/1967538.pdf
Data publikacji:
2019-12-31
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
peer tutoring
communication
collaboration
academic achievement
tutee
tutor
Opis:
The objective of this study was to examine the effect of peer tutoring on college students’ academic achievement and, as well, their competencies in communication and collaboration. In particular, we investigated whether or not the effect of peer tutoring depends on the role taken in peer tutoring. 373 Korean college students attending peer tutoring participated in this study. A pre-post design employing a self-report questionnaire was used. The results indicated that peer tutoring improved both academic achievement and communicative and collaborative skills. The findings also suggested that the effect of peer-tutoring on academic achievement and responsibility for teamwork was valid only with regard to those in the role of tutees. The implications of this study are discussed.
Źródło:
The New Educational Review; 2019, 58; 97-106
1732-6729
Pojawia się w:
The New Educational Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Atmospheric-Pressure Gas-Plasma Treatment on Surface Properties of Hot-Dip Zn-Mg-Al Alloy-Coated Steel
Autorzy:
Jeong, Chang-U
Kim, Jae-Hyeon
Park, Je-Shin
Kim, Min-Su
Kim, Sung-Jin
Oh, Min-Suk
Powiązania:
https://bibliotekanauki.pl/articles/2203736.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
plasma treatment
Zn-Mg-Al-galvanized steel
surface energy
process gas
Opis:
The effect of plasma-radical change on the surface properties of Zn-Mg-Al ternary-alloy-coated steel sheets during atmospheric-pressure (AP) plasma treatment using different process gases: O2, N2, and compressed air was investigated. The plasma-induced radicals promoted the formation of chemical particles on the surface of the Zn-Mg-Al coating, thereby increasing the surface roughness. The surface energy was calculated using the Owen-Wendt geometric equation. Contact angle measurements indicated that the surface free energy of the alloy sheets increased upon AP plasma treatment. The surface properties of the Zn-Mg-Al coating changed more significantly in the order air > O2 > N2 gas, indicating that the plasma radicals facilitated the carbonization and hydroxylation of the Mg and Al components during the AP plasma treatment.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 187--190
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Fe-Mn Solid Solution Precursor Addition on Modified AA 7075
Autorzy:
Kim, Min Sang
Kim, Dae Young
Kim, Young Do
Choi, Hyun Joo
Kim, Se Hoon
Powiązania:
https://bibliotekanauki.pl/articles/2049310.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-Zn-Mg alloy
solid solution precursor
mechanical properties
Opis:
This study suggests a new way to modify the size and morphology of Al-Fe phases in modified AA 7075 by using an Fe-Mn solid solution powder as the precursor. When Fe and Mn are added in the form of a solid solution, the diffusion of Fe and Mn toward the Al is delayed, thus altering the chemical composition and morphology of the precipitates. The fine, spherical precipitates are found to provide a good balance between strength and ductility compared to the case where Fe and Mn are separately added.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 3; 783-787
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of CO2 Capture Property of CaO Sorbent in Various Molten Chloride Media with Different Operation Temperature
Autorzy:
Kim, Sung-Wook
Jeon, Min Ku
Lee, Kirak
Powiązania:
https://bibliotekanauki.pl/articles/353567.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
radioactive carbon
14C
CO2 capture
CaO sorbent
molten salt
Opis:
CaO sorbent dissolved in chloride molten salts was investigated to identify its CO2 capture property. Various molten salt systems with different melting points (CaCl2 , LiCl, LiCl-CaCl2 , and LiCl-KCl) were used to control the operation temperature from 450 to 850ºC in order to determine the effect of the operation temperature on the chemical reaction between CaO and CO2 . The CaO sorbent showed the best performance at 550ºC in the LiCl-CaCl2 molten salt (conversion ratio of 85.25%). This temperature is lower than typical operation temperature of the solid-state CaO sorbent (~700ºC).
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 3; 1051-1055
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Effects of Experience and the Presence of a Scaffold Handrail on Postural and Spinal Stability in Construction Workers
Autorzy:
Min, S. N.
Kim, J. Y.
Parnianpour, M.
Powiązania:
https://bibliotekanauki.pl/articles/91154.pdf
Data publikacji:
2014
Wydawca:
Centralny Instytut Ochrony Pracy
Tematy:
fall
low back pain
postural stability
lumbar stability
construction
injury
ból pleców
stabilność postawy
pracownicy budowlani
rusztowanie budowlane
Opis:
The goal of this study was to quantify the effect of experience and handrail presence on trunk muscle activities, rotational spinal stiffness and postural stability of construction workers. We evaluated spinal stability, and objective and subjective postural stability in 4 expert and 4 novice construction workers who were performing a manual task in a standing position on a scaffold, with and without a safety handrail. Center of pressure was computed using measurements taken with insole pressure transducers. Muscle activity was monitored usingsurface electrodes placed on 8 trunk muscles that predicted active trunk rotational stiffness. Standard deviations of the center of pressure, back muscle activity and spinal stiffness were greater in novices and in the absence of a handrail. We infer that the risk of a fall due to postural and spinal instability may be greater with a lower level of experience and in the absence of a safety handrail.
Źródło:
International Journal of Occupational Safety and Ergonomics; 2014, 20, 3; 491-502
1080-3548
Pojawia się w:
International Journal of Occupational Safety and Ergonomics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Morphology and Molecular Phylogeny of the Soil Ciliate Anteholosticha rectangula sp. nov. from King George Island, Maritime Antarctica
Autorzy:
JUNG, Jae-Ho
Kim, Sanghee
Park, Kyung-Min
Powiązania:
https://bibliotekanauki.pl/articles/763599.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Tematy:
New species, protargol impregnation, polyphyly, SSU rDNA, taxonomy
Opis:
The soil ciliate Anteholosticha rectangula nov. spec. was discovered on King George Island in maritime Antarctica. Morphology and the nuclear SSU rDNA sequence were used to describe and infer the phylogenetic position of the new species. Anteholosticha rectangula is morphologically similar to A. bergeri and A. verrucosa, differing primarily by the morphology of the nuclear apparatus and dorsal kineties, respectively. The morphological features of related species are compared and discussed to confirm the validity of the new species. Molecular phylogenetic tree supports the previously reported polyphyly of the genus Anteholosticha.
Źródło:
Acta Protozoologica; 2016, 55, 2
1689-0027
Pojawia się w:
Acta Protozoologica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Aspect Ratio on Iron-Ore Briquettes During Twin-Roll Briquetting
Autorzy:
Kim, Kang-Min
Bae, Jong-Ho
Han, Jeong-Whan
Powiązania:
https://bibliotekanauki.pl/articles/355616.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
numerical analysis
discrete element method
roll briquetting
Opis:
In the ironmaking, sizes of raw materials such as iron ores and coke must be adjusted for subsequent process in the blast furnace. The depletion of high grade iron ore in recent years necessitates a technology that can utilize low-grade fine iron ores. Thus, steelmakers have been studying the sinter-briquette complex firing process that employs a method of charging the sinter feed together with briquettes made of fine iron ore. In this process, larger briquettes increase the briquette productivity per unit time but decrease the green strength of briquettes and they can break during transportation and charging. Thus, the briquette shape is very important. Therefore, in this study, we simulate a twin roll briquetting process using the DEM analysis and compared the compressive force distributions in the briquette for different aspect ratios. This study is a new attempt, because research cases by numerical methods on the same or similar systems are very rare. Consequently, the optimal aspect ratio is 0.5 at briquette height 20 mm, 2.0 at 30 mm, and 1.5 at 40 mm. Also, the average compressive force increased in proportion with the pocket height at the sameaspect ratio. Therefore, to increase the pocket depth for high productivity, the pocket height must also be increased for obtaining high strength briquettes.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1335-1339
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructural Evolution of Sinter-Forged Fe-Cr-Mo-C Alloy Depending on Cu Addition
Autorzy:
Oh, Min Chul
Kim, Moontae
Lee, Jisung
Ahn, Byungmin
Powiązania:
https://bibliotekanauki.pl/articles/355446.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Astaloy CrL
Fe-based alloy
pre-alloyed powder
powder forging
microstructure
Opis:
Pre-alloyed Astaloy CrLTM (Fe-1.5 wt% Cr-0.2 wt% Mo), a commercial Fe-based alloy powder for high strength powder metallurgy products, was sintered and hot forged with additions of 0.5 wt% C and 0~2 wt% Cu. To investigate the influence of various Cu contents, the microstructural evolution was characterized using density measurements, scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). Transverse rupture strength (TRS) was measured for each composition and processing stage. The correlation between Cu additions and properties of sinter-forged Fe-Cr-Mo-C alloy was discussed in detail.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 539-542
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Post-Heat Treatment on the Impact Toughness and Crack Propagation Mechanism of AISI D2 Tool Steel Manufactured by Direct Energy Deposition
Autorzy:
Park, Jun-Hyung
Kim, Kyu-Sik
Koo, Yong-Mo
Kim, Jin-Young
Kim, Min-Chul
Lee, Kee-Ahn
Powiązania:
https://bibliotekanauki.pl/articles/2203722.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AISI D2 tool steel
direct energy deposition
post-heat treatment
impact toughness
fractography
Opis:
This study investigated the effect of heat treatment on the microstructure and impact toughness property of AISI D2 manufactured with direct energy deposition (DED) and compared the results with conventional wrought material. The fracture crack propagation behavior was examined in connection with microstructures through fracture surface analysis. AISI D2 manufactured with DED had a eutectic structure that turned into a net-type carbide after heat treatment, and Cr-rich needle-type secondary carbide was observed. Impact toughness of DED AISI D2 measured 2.0 J/cm2 in the as-built sample and 1.1 J/cm2 in the heat-treated sample. Compared to a wrought heat-treated AISI D2, DED AISI D2 had relatively low impact toughness. DED AISI D2 and wrought material had different crack propagation mechanisms. In DED AISI D2, the eutectic structure and net-type carbide boundary were identified as the major microstructural factor decreasing impact toughness.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 119--122
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of Aluminum Matrix Composite Reinforced with Al0.5CoCrCuFeNi High-Entropy Alloy Particles
Autorzy:
Kim, Min Sang
Son, Han Sol
Joo, Gyeong Seok
Kim, Young Do
Choi, Hyun Joo
Kim, Se Hoon
Powiązania:
https://bibliotekanauki.pl/articles/2174583.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum matrix composite
high entropy alloys
reinforcement
powder-in-tube
stir casting
Opis:
The aluminum composite with dispersed high entropy alloy were developed by stir casting involving the powder-in-tube method. First, Al0.5CoCrCuFeNi high entropy alloy (HEA) powder was made by mechanical alloying, and the powder was extruded in a tube-type aluminum container to form HEA precursor. The extruded HEA precursor was then dispersed in the aluminum matrix via stir casting. As a result, Fe-Cr-Ni based high-entropy phases was uniformly formed in the aluminum matrix, revealing ~158, 166, 235% enhancement of tensile strength by incorporating 1, 3, and 5 wt% HEA particles, respectively.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1543--1546
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Improvement of Weldability of Hot-Dip Galvanized Steel by Anti-Galvanizing Coating with Si-Fe-Al Oxide-Based Micropowder
Autorzy:
So, Seong-Min
Kim, Ki-Yeon
Park, Il-Song
Lee, Seok-Jae
Yoo, Dong-Jin
Kim, Yeon-Won
Oh, Min-Suk
Powiązania:
https://bibliotekanauki.pl/articles/2203718.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hot-dip galvanizing
anti-galvanizing
oxide micropowder
weldability
Opis:
A Si-Fe-Al ternary oxide-based micropowder coating was used to prevent the formation of a Zn coating on steel during the hot-dip Zn galvanizing process to reduce the welding fume and defects generated during the welding of Zn-galvanized steel. The composition ratio of the oxide powder was optimized and its microstructure and weldability were evaluated. The optimized oxide coating was stable in the hot-dip galvanizing bath at 470°C and effectively inhibited the formation of Zn coating. The Zn residue could be easily removed with simple mechanical impact. The proposed coating reduced Zn fume and prevented the residual Zn from melting in the weld bead during high-temperature welding, thus reducing the number of welding defects. The results indicated that this pretreatment can simplify the manufacturing process and shorten the process time cost-effectively.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 155--159
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Deflector Plate for Particle Size Segregation Control
Autorzy:
Kim, Kang-Min
Kim, Ju-Hun
Kwon, Jae-Hong
Lee, Ji-A
Han, Jeong-Whan
Powiązania:
https://bibliotekanauki.pl/articles/353855.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
size segregation
numerical analysis
discrete element method
Opis:
In general, uniform mixing of particles is desirable in the process of particle handling. However, during the charging of sinter feed and upper ore, size segregation must be induced to prevent heat imbalance, ensure bed permeability, and prevent the loss of fine ore. In this study, upper ore charging was simulated using a discrete element method (DEM) to find the optimal method for controlling particle size segregation, and the segregation characteristics in the upper ore bed were investigated when a deflector plate was applied to the charging machine. The degree of vertical segregation increased when a deflector plate was applied, and it was confirmed that the segregation direction in the upper ore bed can be controlled by adjusting the charging direction of the upper ore by using a deflector plate. In order to apply this method directly to the actual process, further study is needed to understand the influence of the characteristics of the deflector plate such as length and angle.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 495-500
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Controlled Porosity on the Mechanical Properties of Ti-Zr-Sn-Mo Biomedical Alloys
Autorzy:
Kim, Yeon-Wook
Erlangga, Bagus D.
Do, Dalhyun
Lee, Seong-Min
Powiązania:
https://bibliotekanauki.pl/articles/352474.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ti-Zr-Sn-Mo alloy
porous scaffolds
biomedical materials
shape memory alloys
Opis:
In this study, a simple and effective way to fabricate highly porous scaffolds with controlled porosity and pore size is demonstrated. Ti-7Zr-6Sn-3Mo shape memory alloy fibers were prepared through a melt overflow process. The scaffolds with porosity of 65-85% and large pores of 100-700 μm in size were fabricated by sintering the as-solidified fibers. Microstructures and transformation behaviors of the porous scaffolds were investigated by means of SEM, DSC and XRD. The scaffolds were composed of β phase at room temperature. Superelasticity with the superelastic recovery strain of 7.4% was achieved by β↔α”phase transformation. An effect of porosity on mechanical properties of porous scaffolds was investigated by using compressive test. As the porosity increased from 65% to 85%, elastic modulus and compressive strength decreased from 0.95 to 0.06 GPa and from 27 to 2 MPa, respectively.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 4; 1341-1344
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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