Autor: Choi, J.-S. - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: The Effect Of Grain Size On The Mechanical Properties Of Aluminum
Wpływ wielkości ziarna na właściwości mechaniczne aluminium
Autorzy:: Jeong, G.
Park, J.
Nam, S.
Shin, S.-E.
Shin, J.
Bae, D.
Choi, H.
Powiązania:: https://bibliotekanauki.pl/articles/351200.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: nanocrystalline aluminum
grain size
microstructure
mechanical properties
tensile behavior
aluminium
wielkość ziarna
mikrostruktura
rozciąganie
właściwości mechaniczne
Opis:: Although many studies have focused on the unique plastic deformation behavior of nanocrystalline aluminum (e.g., the positive deviation from Hall-Petch relation, the unusual yield-drop phenomenon in tensile mode, etc.), the data reported by different research groups are inconsistent with each other, possibly because of different fabrication processes. In this study, aluminum samples with a wide grain-size spectrum – from a few micrometers down to 100 nanometers – are manufactured by powder metallurgy. The grain size was measured by X-ray diffraction analysis and transmission electron microscope observation. Furthermore, the tensile behavior, which varied according to a grain size, is discussed with a comparison of the theoretical models.
Źródło:: Archives of Metallurgy and Materials; 2015, 60, 2B; 1287-1291
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Oxide Formation In Metal Injection Molding Of 316L Stainless Steel
Tworzenie tlenków podczas wtryskiwania proszku stali nierdzewnej 316L
Autorzy:: Jang, J. M.
Lee, W.
Ko, S.-H.
Han, C.
Choi, H.
Powiązania:: https://bibliotekanauki.pl/articles/351352.pdf
Data publikacji:: 2015
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:: powder injection molding
sintering
316L stainless steel
sintering atmosphere
micro parts
wtryskiwanie proszku
spiekanie
stal nierdzewna 316L
mikro-część
Opis:: The effects of sintering condition and powder size on the microstructure of MIMed parts were investigated using water-atomized 316L stainless steel powder. The 316L stainless steel feedstock was injected into micro mold with micro features of various shapes and dimensions. The green parts were debound and pre-sintered at 800°C in hydrogen atmosphere and then sintered at 1300°C and 1350°C in argon atmosphere of 5torr and 760torr, respectively. The oxide particles were formed and distributed homogeneously inside the sample except for the outermost region regardless of sintering condition and powder size. The width of layer without oxide particles are increased with decrease of sintering atmosphere pressure and powder size. The fine oxides act as the obstacle on grain growth and the high sintering temperature causes severe grain growth in micro features due to larger amount of heat gain than that in macro ones.
Źródło:: Archives of Metallurgy and Materials; 2015, 60, 2B; 1281-1285
1733-3490
Pojawia się w:: Archives of Metallurgy and Materials
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Influence of InAs Coverage on Transition of Size Distribution and Optical Properties of InAs Quantum Dots
Autorzy:: Kim, G.
Jeon, S.
Cho, M.
Choi, H.
Kim, D.
Kim, M.
Kwon, Y.
Choe, J.
Kim, J.
Leem, J.
Powiązania:: https://bibliotekanauki.pl/articles/1535820.pdf
Data publikacji:: 2010-10
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 81.15.Hi
68.37.Ps
78.55.Cr
78.67.Hc
Opis:: The influence of InAs coverage on the formation of self-assembled quantum dots grown by molecular-beam epitaxy was investigated by atomic force microscopy and photoluminescence measurements. As the InAs coverage increased from 2.0 to 3.0 monolayers, the quantum dot density decreased from 1.1 × $10^{11}$ to 1.36 × $10^{10} cm^{-2}$. This result could be attributed to the coalescence of neighboring small InAs quantum dots resulting in the formation of much larger InAs quantum dots with lower quantum dot density. Atomic force microscopy results revealed that as the InAs quantum dot coverage increased, the transition of size distribution of InAs quantum dots from single-modal to multimodal occurred. The temperature-dependent photoluminescence spectra showed that the photoluminescence spectra red shifted and the photoluminescence peak intensity decreased as the InAs coverage increased. The thermal activation energy was strongly dependent on the InAs coverage, and for InAs quantum dots with 3.0 ML thick InAs coverage, this energy was estimated to be 147 meV.
Źródło:: Acta Physica Polonica A; 2010, 118, 4; 673-676
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Optical Properties of Multi-Stacked InAs Quantum Dots Embedded in GaAs/InGaAs Strained Layer and its Annealing Behaviors
Autorzy:: Kim, D.
Kim, G.
Jeon, S.
Cho, M.
Choi, H.
Kim, M.
Lee, D.
Kim, J.
Eom, G.
Leem, J.
Powiązania:: https://bibliotekanauki.pl/articles/1537752.pdf
Data publikacji:: 2010-06
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 78.67.Hc
78.55.Cr
81.05.Ea
Opis:: Multi-stacked InAs QDs embedded in ten periods of GaAs/$In_{0.1}Ga_{0.9}As$ strained layers were grown by MBE and their optical properties were investigated by using PL spectroscopy. For the QDs embedded in ten periods of GaAs/$In_{0.1}Ga_{0.9}As$ strained layers, the PL intensity is enhanced about 4.7 times and a narrower FWHM of 26 meV is observed compared to those of the conventional multi-stacked QDs. The PL spectra of the InAs QDs show blue-shifts of about 50 meV with increasing annealing temperature up to 850°C. At annealing temperature of 600°C, the FWHM of the PL peak is reduced to 16 meV and PL intensity is enhanced compared to those of the as-grown sample, which indicates improvement of size uniformity and crystal quality of the QDs.
Źródło:: Acta Physica Polonica A; 2010, 117, 6; 941-944
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Fabrication and Characterization of GaN/Polymer Composite p-n Junction with PEDOT Nanoparticle Interface Layer
Autorzy:: Kim, M.
Jin, S.
Choi, H.
Kim, G.
Yim, K.
Kim, S.
Nam, G.
Yoon, H.
Kim, Y.
Lee, D.
Kim, Jin
Kim, Jong
Leem, J.
Powiązania:: https://bibliotekanauki.pl/articles/1505152.pdf
Data publikacji:: 2011-06
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 73.61.Ey
81.15.Gh
Opis:: A heavily Si-doped GaN/polymer hybrid structure with p-type poly(3,4-ethylene-dioxythiophene):beta-1,3-glucan (PEDOT nanoparticle) interface layer has been fabricated. The Si-doped GaN thin film with carrier concentration of 1 × $10^{19} cm^{-3}$ was grown by metal-organic chemical vapor deposition. The PEDOT nanoparticle with various sizes ranging from 60 to 120 nm was synthesized via a miniemulsion polymerization process. The electrical conductivity of the PEDOT nanoparticle is less than 1.2 S/cm. The current-voltage (I-V) characteristic of the hybrid structure shows diode-like behavior. The I-V characteristic was examined in the framework of the thermionic emission model. The ideality factor of the structure without PEDOT nanoparticle interface layer is 12.9. However, the ideality factor of the hybrid structure with PEDOT nanoparticle interface layer is obtained as 1.9. The value of ideality factor is dramatically decreased by inserting the PEDOT nanoparticle interface layer.
Źródło:: Acta Physica Polonica A; 2011, 119, 6; 875-879
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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