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Wyszukujesz frazę "Kim, Dong" wg kryterium: Autor


Wyświetlanie 1-13 z 13
Tytuł:
Average convergence rate of the first return time
Autorzy:
Choe, Geon
Kim, Dong
Powiązania:
https://bibliotekanauki.pl/articles/965737.pdf
Data publikacji:
2000
Wydawca:
Polska Akademia Nauk. Instytut Matematyczny PAN
Tematy:
entropy
the first return time
period of an irreducible matrix
Wyner-Ziv-Ornstein-Weiss theorem
data compression
Markov chain
Opis:
The convergence rate of the expectation of the logarithm of the first return time $R_{n}$, after being properly normalized, is investigated for ergodic Markov chains. I. Kontoyiannis showed that for any β > 0 we have $log[R_{n}(x)P_{n}(x)] =o(n^{β})$ a.s. for aperiodic cases and A. J. Wyner proved that for any ε >0 we have $-(1 + ε)log n ≤ log[R_{n}(x)P_{n}(x)] ≤ loglog n$ eventually, a.s., where $P_{n}(x)$ is the probability of the initial n-block in x. In this paper we prove that $ E[log R_{(L,S)} - (L-1)h]$ converges to a constant depending only on the process where $R_{(L,S)}$ is the modified first return time with block length L and gap size S. In the last section a formula is proposed for measuring entropy sharply; it may detect periodicity of the process.
Źródło:
Colloquium Mathematicum; 2000, 84/85, 1; 159-171
0010-1354
Pojawia się w:
Colloquium Mathematicum
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stress Corrosion Cracking Properties of Steam Generator Tubing Alloys in Crevice Environment
Autorzy:
Shin, Jung-Ho
Kim, Dong-Jin
Powiązania:
https://bibliotekanauki.pl/articles/351858.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stress corrosion
nickel base alloy
nuclear plants
secondary side
passive film
Opis:
The safe and reliable operation of pressurized water reactors (PWRs) depends on the integrity of structural material. In particular, the failure of steam generator (SG) tubes on the secondary side is one of the major concerns of operating nuclear power plants. To establish remediation techniques and manage damage, it is necessary to articulate the mechanism through which various impurities affect the SG tubes. This research aims to understand the effect of impurities (e. g., S, Pb, and Cl) on the stress corrosion cracking of Alloy 600 and 690.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 543-545
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality of Algebraic Numeration Problems to Measure Higher Order Thinking Skills Using Partial Credit Model
Autorzy:
Harvani, Indah Dwi
Kurniati, Dian
Kim, Dong-Joong
Osman, Sharifah
Powiązania:
https://bibliotekanauki.pl/articles/2233931.pdf
Data publikacji:
2023-06-30
Wydawca:
Wydawnictwo Adam Marszałek
Tematy:
algebraic numeration problems
higher-order thinking skills
partial
credit model
Opis:
Higher-order thinking skills are abilities that all students must possess. Students are given algebraic numeracy questions to measure this ability. This research aims to determine the quality of algebraic numeracy questions based on their validity and reliability. This type of research is quantitative, with analysis using a partial credit model with 28 students as research subjects. The results in this study were that the 10 numeration questions developed were valid because they met at least one of the validity and reliability criteria with an item reliability value of 0.82, indicating that the instrument could measure high-level thinking skills well.
Źródło:
The New Educational Review; 2023, 72; 218-229
1732-6729
Pojawia się w:
The New Educational Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of Pure Ti Implants Fabricated by Additive Manufacturing
Autorzy:
Kim, Dong-Jin
Kim, Hyung-Giun
Kim, Ji-Sun
Song, Kuk-Hyun
Powiązania:
https://bibliotekanauki.pl/articles/354362.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
pure Ti
selected laser melting
heat input
microstructure
mechanical property
Opis:
This study was carried out to evaluate the aspect of microstructure and mechanical property development on additive manufactured pure Ti at elevated heat-input. For this work, pure Ti powder (commercial purity, grade 1) was selected, and selective laser melting was conducted from 0.5 to 1.4 J/mm. As a result, increase in heat-input led to the significant grain growth form 4 μm to 12 μm, accompanying with the change of grain shape, correctly widmanstätten structured grains. In addition, Vickers microhardness was notably increased from 228 Hv to 358 Hv in accordance with elevated heat-input, which was attributed to the increased concentration of oxygen and nitrogen mainly occurred during selected laser melting process.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 959-962
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of NF3 Gas on Stabilization of Alkaline Earth Metal-Cu Mordenite Catalysts During N2O Decomposition Reaction
Autorzy:
Seo, Minhye
Lee, Soo-Young
Cho, Sung-Su
Song, Hyoung Woon
Kim, Hyun-Kyung
Kim, Dong Soo
Lee, Sungkyu
Powiązania:
https://bibliotekanauki.pl/articles/947575.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nitrous oxide
N2O
nitrofluorine three
NF3
perfluorocompounds
PFCs
direct decomposition
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 695-700
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heat Treatment Effect on Physical Properties of Stainless Steel / Inconel Bonded by Directed Energy Deposition
Autorzy:
Eom, Yeong Seong
Kim, Kyung Tae
Kim, Dong Won
Yu, Ji-Hun
Sim, Chul Yong
An, Seung Jun
Park, Yong-Ha
Son, Injoon
Powiązania:
https://bibliotekanauki.pl/articles/2049122.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
directed energy deposition
interface
physical properties
heat treatment
Opis:
In this study, stainless steel 316L and Inconel 625 alloy powders were additively manufactured by using directed energy deposition process. And heat treatment effect on hardness and microstructures of the bonded stainless steel 316L/Inconel 625 sample was investigated. The microstructures shows there are no secondary phases and big inclusions near interfacial region between stainless steel 316L and Inconel 625 except several small cracks. The results of TEM and Vickers Hardness show the interfacial area have a few tens of micrometers in thickness. Interestingly, as the heat treatment temperature increases, the cracks in the stainless steel region does not change in morphology while both hardness values of stainless steel 316L and Inconel 625 decrease. These results can be used for designing pipes and valves with surface treatment of Inconel material based on stainless steel 316L material using the directed energy deposition.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 4; 1049-1054
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Soaking Soybean Seeds with Abeliophyllum distichum Nakai Extract Increased the Yield and Nutritional Value of Soybean Sprouts
Autorzy:
Kim, Jeong-Ho
Yoon, Yong-Han
Dhungana, Sanjeev Kumar
Kim, Il-Doo
Shin, Dong-Hyun
Powiązania:
https://bibliotekanauki.pl/articles/2051042.pdf
Data publikacji:
2022-06-02
Wydawca:
Instytut Rozrodu Zwierząt i Badań Żywności Polskiej Akademii Nauk w Olsztynie
Tematy:
amino acid
color parameters
isoflavone
mineral
vitamin C
Opis:
Abeliophyllum distichum Nakai, an ornamental plant, contains a wide range of phytochemicals having pharmaceutical properties. The use of different plant-based extracts for the enhancement of yield and/or quality of soybean sprouts, one of the most inexpensive but nutritious food products, is common. The objective of this study was to examine the effect of A. distichum flower extract (ADE) on the yield and nutritional value of soybean sprouts. Soybean seeds were soaked in ADE solutions with concentrations (w/v) of 0.5% (ADE-0.5), 1% (ADE-1), 3% (ADE-3), and 5% (ADE-5). The effect of ADE concentration on the yield and different nutrient components varied. The highest soybean sprout yield and vitamin C content were found with ADE-3. The most abundant essential amino acid content was detected in ADE-1, whereas the greatest amounts of total isoflavones and total minerals were determined in ADE-5 and the ADE-untreated control, respectively. Overall results of yield, color, and contents of vitamin C, amino acids, and isoflavones suggest that 1% or 3% of A. distichum extract could be an optimum concentration to soak the soybean seeds for higher sprout yield and nutrient content.
Źródło:
Polish Journal of Food and Nutrition Sciences; 2022, 72, 2; 151-158
1230-0322
2083-6007
Pojawia się w:
Polish Journal of Food and Nutrition Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and High Temperature Oxidation Properties of Fe-Cr-Ni HK30 Alloy Manufactured by Metal Injection Molding
Autorzy:
Wi, Dong-Yeol
Kim, Young-Kyun
Yoon, Tae-Sik
Lee, Kee-Ahn
Powiązania:
https://bibliotekanauki.pl/articles/356708.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metal injection molding
HK30
microstructure
high temperature oxidation
Opis:
This study investigated the microstructure and high temperature oxidation properties of Fe-25Cr-20Ni-1.5Nb, HK30 alloy manufactured by metal injection molding (MIM) process. The powder used in MIM had a bi-modal size distribution of 0.11 and 9.19 μm and had a spherical shape. The initial powder consisted of γ-Fe and Cr23C6 phases. Microstructural observation of the manufactured (MIMed) HK30 alloy confirmed Cr23C6 along the grain boundary of the γ-Fe matrix, and NbC was distributed evenly on the grain boundary and in the grain. After a 24-hour high temperature oxidation test at air atmospheres of 1000, 1100 and 1200°C, the oxidation weight measured 0.72, 1.11 and 2.29 mg/cm2, respectively. Cross-sectional observation of the oxidation specimen identified a dense Cr2O3 oxide layer at 1000°C condition, and the thickness of the oxide layer increased as the oxidation temperature increased. At 1100°C and 1200°C oxidation temperatures, Fe-rich oxide was also formed on the dense Cr2O3 oxide layer. Based on the above findings, this study identified the high-temperature oxidation mechanism of HK30 alloy manufactured by MIM.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 525-530
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research the Integration of Geodetic and Geotechnical Methods in Monitoring the Horizontal Displacement of Diaphragm Walls
Autorzy:
Pham, Quoc Khanh
Tran, Ngoc Dong
Nguyen, Thi Kim Thanh
Pham, Van Chung
Powiązania:
https://bibliotekanauki.pl/articles/2020165.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Przeróbki Kopalin
Tematy:
deformation monitoring
diaphragm wall
engineering surveying
soft ground
deformacje
monitoring
grunt
Opis:
This article investigates the integration of geodetic and geotechnical methods for monitoring the horizontal displacement of diaphragm walls. The results show that when the horizontal displacement is measured by the geotechnical method using an inclinometer sensor, the center point at the bottom of the guide pipe is usually chosen to be the origin to calculate displacements of the upper points. However, it is challenging to survey the bottom point for checking its stability directly. If this bottom point moves, the observation results will be incorrect. Thus, the guide pipe must be installed in the stable rock layer. But in the soft ground, this rock layer locates more deeply than the diaphragm walls, so the guide pipe cannot be laid out at the required location. Geodetic methods can directly observe the displacement of the center point on the top of the guide pipe with absolute displacement values at high accuracy. Because the displacements of observation points are determined at stable benchmarks, these values are considered the pipe's displacement. Thus, an integrated solution allows the center point on the top of the pipe to be the origin to calculate the displacements of different points located inside the diaphragm wall. Then, the calculated values are calibrated back to the inclinometer observed values to achieve highly reliable displacement, which reflects the moving of diaphragm walls. An experiment integrating the geodetic and geotechnical methods is conducted with an observation point at a depth of 20 meters at a construction site in Ho Chi Minh city. The deviations of the top point that are observed by the two methods are -4.37 millimeters and -3.69 millimeters on the X-axis and the Y-axis, respectively. The corrected observed results prove that the integrated solution has a good efficiency in monitoring the horizontal displacement of diaphragm walls. The bottom point observed by an inclinometer is unconfident enough to choose to be a reference point.
Źródło:
Inżynieria Mineralna; 2021, 2; 331--340
1640-4920
Pojawia się w:
Inżynieria Mineralna
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:
High-Efficiency Cooling System Using Additive Manufacturing
Autorzy:
Woo, Yeong-Jin
Nam, Dong-Ho
Lee, Seok-Rok
Kim, Eun-Ah
Lee, Woo-Jin
Yang, Dong-Yeol
Yu, Ji-Hun
Park, Yong-Ho
Lee, Hak-Sung
Powiązania:
https://bibliotekanauki.pl/articles/2049198.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
additive manufacturing
DfAM
Design for Additive Manufacturing
cooling system
lattice structure
simulation
Opis:
In this study, we propose a cooling structure manufactured using a specialized three-dimensional (3D) printing design method. A cooling performance test system with complex geometry that used a thermoelectric module was manufactured using metal 3D printing. A test model was constructed by applying additive manufacturing simulation and computational fluid analysis techniques, and the correlation between each element and cooling efficiency was examined. in this study, the evaluation was conducted using a thermoelectric module base cooling efficiency measurement system. The contents were compared and analyzed by predicting the manufacturing possibility and cooling efficiency, through additive manufacturing simulation and computational fluid analysis techniques, respectively.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 3; 689-693
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dual Speed Laser Remelting for High Densification in H13 Tool Steel Metal 3D Printing
Autorzy:
Jung, Im Doo
Choe, Jungho
Yun, Jaecheol
Yang, Sangsun
Yang, Dong-Yeol
Kim, Yong-Jin
Yu, Ji-Hun
Powiązania:
https://bibliotekanauki.pl/articles/353737.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
metal 3d printing
powder bed fusion
selective laser melting
H13 tool steel
remelting
Opis:
The densification behavior of H13 tool steel powder by dual speed laser scanning strategy have been characterized for selective laser melting process, one of powder bed fusion based metal 3d printing. Under limited given laser power, the laser re-melting increases the relative density and hardness of H13 tool steel with closing pores. The single melt-pool analysis shows that the pores are located on top area of melt pool when the scanning speed is over 400 mm/s while the low scanning speed of 200 mm/s generates pores beneath the melt pool in the form of keyhole mode with the high energy input from the laser. With the second laser scanning, the pores on top area of melt pools are efficiently closed with proper dual combination of scan speed. However pores located beneath the melt pools could not be removed by second laser scanning. When each layer of 3d printing are re-melted, the relative density and hardness are improved for most dual combination of scanning. Among the scan speed combination, the 600 mm/s by 400 mm/s leads to the highest relative density, 99.94% with hardness of 53.5 HRC. This densification characterization with H13 tool steel laser re-melting can be efficiently applied for tool steel component manufacturing via metal 3d printing.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 571-578
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Deformation of Tungsten Diselenide Nanostructures Induced by Ozone Oxidation and Investigation of Electronic Properties Change
Autorzy:
Kim, Eunjeong
Lee, Sangyoeb
Je, Yeonjin
Lee, Dong Park
Park, Sang Jun
Jeong, Sanghyun
Park, Joon Sik
Ahn, Byungmin
Park, Jun Hong
Powiązania:
https://bibliotekanauki.pl/articles/2176647.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tungsten diselenide
domain boundary
ozone oxidation
structural deformation
scanning tunneling microscopy
Opis:
Tungsten diselenide (WSe2) is one of the promising transition metal dichalcogenides (TMDs) for nanoelectronics and opto-electronics. To enhance and tune the electronic performance of TMDs, chemical functionalization via covalent and van der Waals approaches has been suggested. In the present report, the electric and structural transition of WSe2 oxidized by exposure to O3 is investigated using scanning tunneling microscopy. It is demonstrated that the exposure of WSe2/high-ordered pyrolytic graphite sample to O3 induces the formation of molecular adsorbates on the surface, which enables to increase in the density of states near the valence band edge, resulting from electric structural modification of domain boundaries via exposure of atomic O. According to the work function extracted by Kelvin probe force microscopy, monolayer WSe2 with the O3 exposure results in a gradual increase in work function as the exposure to O3. Therefore, the present report demonstrates the potential pathway for the chemical functionalization of TMDs to enhance the electric performance of TMDs devices.
Źródło:
Archives of Metallurgy and Materials; 2022, 67, 4; 1469--1473
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-13 z 13

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