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


Tytuł:
EPR Paradox Solved by Special Theory of Relativity
Autorzy:
Lee, J.
Tematy:
03.65.Ud
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1198533.pdf  Link otwiera się w nowym oknie
Opis:
This paper uses the special theory of relativity to introduce a novel solution to Einstein-Podolsky-Rosen paradox. More specifically, the faster-than-light communication is described to explain two types of EPR paradox experiments: photon polarization and electron-positron pair spins. Most importantly, this paper explains why this faster-than-light communication does not violate the special theory of relativity.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tiling Spaces of Taylor-Socolar Tilings
Autorzy:
Lee, J.
Tematy:
61.44.Br
61.44.-n
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1373221.pdf  Link otwiera się w nowym oknie
Opis:
The Taylor-Socolar tiling has been introduced as an aperiodic mono-tile tiling. We consider a tiling space which consists of all the tilings that are locally indistinguishable from a Taylor-Socolar tiling and study its structure. It turns out that there is a bijective map between the space of the Taylor-Socolar tilings and a compact Abelian group of a Q-adic space (Q̅) except at a dense set of points of measure 0 in Q̅. From this we can derive that the Taylor-Socolar tilings have quasicrystalline structures. We make a parity tiling from the Taylor-Socolar tiling identifying all the rotated versions of a tile in the Taylor-Socolar tiling by white tiles and all the reflected versions of the tile by gray tiles. It turns out that the Taylor-Socolar tiling is mutually locally derivable from this parity tiling.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural Transformation of Minimal Spanning Trees in World Commodity Market
Autorzy:
Lee, J.
Nobi, A.
Tematy:
89.20.-a
89.65.Gh
89.75.-k
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1029531.pdf  Link otwiera się w nowym oknie
Opis:
We consider structural change of a world trade-flow network for different commodities from 1995 to 2013. A minimum spanning tree is generated from the trade flow data, and we investigate the hierarchical organization of the tree by changing the hub node. Only a few countries are the hub nodes for many of the commodities. We observed the structural transitions, from a chain-like tree (many countries are hub nodes) to a bi-starlike tree (only two countries are hub nodes). In the bi-starlike tree, China and Germany are the only two hub nodes.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sensitizing Effects of Ti Alloying Contents on Damage Behavior of Austenitic Stainless Steel Exposed to Ultrasonic Vibratory Cavitation
Autorzy:
Lee, J.
Kim, S.
Tematy:
47.55.dp
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1186947.pdf  Link otwiera się w nowym oknie
Opis:
The cavitation damage characteristics of austenitic stainless steel with different concentrations of Ti were investigated. The microstructure of the alloys was observed with optical microscope to identify its correlation with cavitation resistance. Hardness of the alloys was measured to examine its contribution to cavitation damage. It was found that the microstructure played a more significant role in cavitation damage behavior of austenitic stainless steel with Ti than the hardness. The findings in this study revealed that Ti addition in austenitic stainless steel may present either a beneficial or detrimental effect on cavitation damage behavior, depending on the microstructural characteristics. In particular, Ti content of 1.0% represented the most deteriorated cavitation characteristics due to the formation of relatively coarse precipitates. Therefore, control of Ti concentration is essential for marine application of austenitic stainless steel.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of applied frequency on microstructural and electrochemical characteristics of ceramic coating produced on Al-Mg alloy by pulsed plasma electrolytic oxidation
Autorzy:
Lee, J.
Lee, S.
Kim, S.
Tematy:
81.16.Pr
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1155322.pdf  Link otwiera się w nowym oknie
Opis:
Plasma electrolytic oxidation (PEO) coating is gaining attention as a promising surface treatment technique for lightweight metals and alloys such as Al, Mg and Ti. The coating involves complex interactions among various process parameters including substrate composition, current modes and electrolyte composition. In this study, ceramic coating was produced in silicate based alkaline solution on Al-Mg alloy by pulsed PEO with different applied frequencies (100, 500, 1000, 2000 Hz). The resultant coating was characterized using FE-SEM, EDS and HR-XRD. The electrochemical characteristics of the PEO coating were also investigated in seawater solution. It was found that changing frequency in the PEO process had a prominent effect on both surface and cross-sectional morphology of the coating. The electrochemical studies indicated that the pulsed PEO have improved the corrosion resistance of the Al-Mg substrate. In particular, the applied frequency of 100 Hz has produced one order of magnitude lower corrosion current density than that of the Al-Mg substrate.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphite Nanosheet Exfoliation From Graphite Flakes Through Functionalization Using Phthalic Acid
Złuszczanie nanoarkuszy grafitu z płatków grafitu przy użyciu kwasu ftalowego
Autorzy:
Kim, J. H.
Lee, J. H.
Tematy:
exfoliation
graphite nanosheet
functionalization
grafting molecule
Friedel-Crafts acylation
złuszczanie
nanoarkusz grafitu
funkcjonalizacja
kwas ftalowy
acylowanie Friedela-Craftsa
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/351457.pdf  Link otwiera się w nowym oknie
Opis:
In order to fabricate graphite nanosheets from graphite flakes, edge-functionalized graphite nanosheets were prepared by a functionalization method using phthalic acid as the molecule to be grafted. A polyphosphoric acid/P2O5 solution containing graphite and phthalic acid were heated at different temperatures for 72 h in a nitrogen atmosphere. It was confirmed by transmission electron microscopy and atomic force microscopy that the resultant phthalic acid-functionalized graphite nanosheets had a large surface area of 20.69 μm2 in average and an average thickness of 1.39 nm. It was also found by X-ray diffractometry and Fourier transform infrared spectroscopy (FT-IR) analysis that the functionalization caused the formation of C=O bonds at the edges of the graphite nanosheets. The yield from this functionalization method was found to be dependent on the reaction temperature, only when it is between 70 and 130°C, because of the dehydration of phthalic acid at higher temperatures. This was confirmed by FT-IR analysis and the observation of low thermal energies at low temperatures.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure Evolution of Tungsten-Based ODS Alloys Reinforced with the γ(Ni, Fe) Phase by a Secondary Ball Milling Method
Autorzy:
Chen, C.
Zeng, Y.
Lee, J.
Tematy:
81.20.Ev
81.20.Wk
81.07.Bc
81.05.Ni
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Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:
https://bibliotekanauki.pl/articles/1375180.pdf  Link otwiera się w nowym oknie
Opis:
In the current study, $W-5Ni-2Fe-Y_2O_3$ model alloys were produced using a high-energy planetary ball mill. The presence of the γ(Ni, Fe) phase is favored with respect to material properties in this alloy. Therefore, a secondary ball milling method was introduced to obtain a fine and uniformly distributed γ(Ni, Fe) phase. Phase development of mechanical alloyed powders was investigated by X-ray diffraction. The results show that the formation of the γ(Ni, Fe) phase was found after 18 h of a pre-milling procedure. A further secondary milling method produced a uniform microstructure with grain refinement. TEM results also show changes in the lattice parameters of the tungsten and γ(Ni, Fe) phase associated with the solid solubility limits in the alloy produced by secondary ball milling.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Preparation of Submicroscale Ag-Coated Cu Particles by Multi-Step Addition of Ag Plating Solution and Antioxidation Properties for Different Ag Shell Thicknesses
Autorzy:
Choi, E. B.
Lee, J.-H.
Tematy:
Ag-coated Cu particle
submicrometer
Glycol-based Ag plating solution
mult-step addition
antioxidation
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/351202.pdf  Link otwiera się w nowym oknie
Opis:
For application as a low-cost conductive filler material, submicroscale Cu@Ag particles were fabricated at room temperature without any reductants by a multi-step addition method using an ethylene glycol-based Ag plating solution. Scanning electron microscopy images of the Ag-coated Cu particles demonstrated the formation of discrete Ag particles less than 100 nm in size as well as a thin Ag coating on Cu particles, during the early addition steps. However, as the thickness of the Ag coating increased, the small Ag particles agglomerated into Ag coatings with an increase in the number of Ag plating steps. Owing to the absence of additives such as surfactants, a comparison between the microstructural images and calculations indicated increased agglomeration between fabricated Ag-coated Cu particles with an increase in the number of Ag plating steps. However, thermogravimetric-differential scanning calorimetry of the agglomerated Ag-coated Cu particles after the fifth addition of the Ag plating solution demonstrated their antioxidation behavior even after 70 min in air at 150°C.
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects Of Process Parameters On Cu Powder Synthesis Yield And Particle Size In A Wet-Chemical Process
Wpływ parametrów procesu na wydajność syntezy proszku Cu i wielkości cząstek w procesie mokrym chemicznym
Autorzy:
Shin, Y. M.
Lee, J. H.
Tematy:
wet-chemical process
micron-size Cu powder
Synthesis yield
particle size
gibbs free energy difference
proszek Cu
proces chemiczny mokry
wydajność syntezy
rozmiar cząsteczki
różnica energii swobodnej Gibbsa
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Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:
https://bibliotekanauki.pl/articles/354168.pdf  Link otwiera się w nowym oknie
Opis:
This study presents a simple wet-chemical process to prepare several micron-size Cu powders. Moreover, changes in powder synthesis yield and particle size are examined with different solvents, synthesis temperatures, and amounts of reducing agent during the synthesis. As a reducing agent and capping agent, L-ascorbic acid and polyvinyl pyrrolidone were used, respectively. The yields in distilled water or an ethylene glycol (EG)/distilled water mixture were higher than that in EG alone, and the yield increased with increasing temperature owing to a lower Δ Gred value. Increasing the L-ascorbic acid concentration also increased the yield. The Cu powder synthesized in 3 h at 90°C in distilled water with 272.8 mM of L-ascorbic acid showed the lowest average particle size of 2.52 μm, indicating mechanisms of short burst nucleation and reduced growth via the increased reduction rate of Cu ions. It is estimated that the nucleation step was nearly completed within 10 min in this system. The Cu powders synthesized in an ethylene glycol/distilled water mixture presented an average particle size of 3.76 μm and the highest yield of 87.9%.
Dostawca treści:
Biblioteka Nauki
Artykuł

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