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


Tytuł:
Effect Of Heat-Treatment On Microstructure And Magnetic Properties Of Nanocrystallized Mn-Zn Ferrite Powders
Wpływ obróbki cieplnej na mikrostrukturę i właściwości magnetyczne nanokrystalicznych proszków ferrytu Mn-Zn
Autorzy:
Lee, W. H.
Hong, C. S.
Chang, S. Y.
Powiązania:
https://bibliotekanauki.pl/articles/351552.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high energy ball milling
nanosized particles
crystallite size
magnetic properties
frezowanie kulowe
nanocząstki
wielkości krystalitów
właściwości magnetyczne
Opis:
The initial ferrite powders were subjected to high energy ball milling at 300rpm for 3h, and subsequently heat-treated at 573-1273K for 1h. Based on the observation of microstructure and measurement of magnetic properties, the heat-treatment effect was investigated. The size of initial powders was approximately 70μm. After milling, the powders with approximately 230nm in size were obtained, which were composed of the nano-sized particles of approximately 15nm in size. The milled powders became larger to approximately 550nm after heat-treatment at 973K. In addition, the size of particles increased to approximately 120nm with increasing temperature up to 973K. The coercivity of initial powders was almost unchanged after milling, whereas the saturation magnetization increased. As the heat-treatment temperature increased, the saturation magnetization gradually increased and the maximum coercivity was obtained at 773K.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1347-1350
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Finitely based monoids obtained from non-finitely based semigroups
Autorzy:
Lee, Edmond W. H.
Powiązania:
https://bibliotekanauki.pl/articles/1368164.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Jagielloński. Wydawnictwo Uniwersytetu Jagiellońskiego
Opis:
Presently, no example of non-finitely based finite semigroup $S$ is known for which the monoid $S^1$ is finitely based. Based on a general result of M. V. Volkov, two methods are established from which examples of such semigroups can be constructed.
Źródło:
Universitatis Iagellonicae Acta Mathematica; 2013, 51; 45-49
2084-3828
0083-4386
Pojawia się w:
Universitatis Iagellonicae Acta Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Integrated plant and pathogen‘omics approaches to understanding fungal diseases of wheat
Autorzy:
Rudd, J.J.
Lee, W.-S.
Hammond-Kosack, K.
Kanyuka, K.
Powiązania:
https://bibliotekanauki.pl/articles/81017.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
conference
plant infection
fungal disease
wheat
septoria tritici blotch
intercellular pathogen
leaf damage
RNA sequence
functional genomics
Źródło:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology; 2013, 94, 3
0860-7796
Pojawia się w:
BioTechnologia. Journal of Biotechnology Computational Biology and Bionanotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
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
Artykuł
Tytuł:
Non-Certainty-Equivalent Adaptive Control of a Nonlinear Aeroelastic System
Autorzy:
Lee, K. W.
Singh, S. N.
Powiązania:
https://bibliotekanauki.pl/articles/226734.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aeroelastic wing
adaptive flutter control
nonlinear system
immersion and invariance method
uncertain system
Opis:
The development of a non-certainty-equivalent adaptive control system for the control of a nonlinear aeroelastic system is the subject of this paper. The prototypical aeroelastic wing section considered here includes structural nonlinearity and a single control surface for the purpose of control. Its dynamical model has two-degree-of-freedom and describes the plunge and pitch motion. It is assumed that the model parameters (except the sign of one of the control input coefficients) are not known. The uncontrolled aeroelastic model exhibits limit cycle oscillation beyond a critical free-stream velocity. Based on the attractive manifold, and the immersion and invariance methodologies, a non-certainty-equivalent adaptive state variable feedback control law for the trajectory tracking of the pitch angle is derived. Using the Lyapunov analysis, asymptotic convergence of the state variables to the origin is established. It is shown that the trajectory of the system converges to a manifold. The special feature of the designed control system is that the closed-loop system asymptotically recovers the performance of a deterministic controller. This cannot happen if certainty-equivalent adaptive controllers are used. Simulation results are presented which show that the control system suppresses the oscillatory responses of the system in the presence of large parameter uncertainties.
Źródło:
International Journal of Electronics and Telecommunications; 2010, 56, 4; 463-471
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Double Step Sintering Behavior Of 316L Nanoparticle Dispersed Micro-Sphere Powder
Dwuetapowe spiekanie mikrosferycznych nanocząstek proszku 316L
Autorzy:
Jeon, B.
Sohn, S. H.
Lee, W.
Han, C.
Kim, Y. D.
Choi, H.
Powiązania:
https://bibliotekanauki.pl/articles/355221.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
316L stainless steel
nanoparticle dispersed micro-sphere
pulse wire explosion
sintering
stal nierdzewna 316L
spiekanie dwuetapowe
mikrosferyczne nanocząstki
Opis:
316L stainless steel is a well-established engineering material and lots of components are fabricated by either ingot metallurgy or powder metallurgy. From the viewpoints of material properties and process versatility, powder metallurgy has been widely applied in industries. Generally, stainless steel powders are prepared by atomization processes and powder characteristics, compaction ability, and sinterability are quite different according to the powder preparation process. In the present study, a nanoparticle dispersed micro-sphere powder is synthesized by pulse wire explosion of 316L stainless steel wire in order to facilitate compaction ability and sintering ability. Nanoparticles which are deposited on the surface of micro-powder are advantageous for a rigid die compaction while spherical micro-powder is not to be compacted. Additionally, double step sintering behavior is observed for the powder in the dilatometry of cylindrical compact body. Earlier shrinkage peak comes from the sintering of nanoparticle and later one results from the micro-powder sintering. Microstructure as well as phase composition of the sintered body is investigated.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1155-1158
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-temperature Oxidation Behavior and Kinetics of Forged 12Cr-MoVW Steel
Autorzy:
Kim, Y. H.
Oak, J.-J.
Bae, K.-C.
Lee, W-J.
Park, Y. H.
Powiązania:
https://bibliotekanauki.pl/articles/351450.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ferritic/martensitic stainless steels
forging
oxidation kinetics
oxide layer
Opis:
The oxidation kinetics of forged 12Cr-MoVW steel was investigated in an air (N2+O2) atmosphere at 873-1073 K (Δ50 K) using thermogravimetric analysis. The oxidized samples were characterized using X-ray diffraction, and the surface and cross-sectional morphologies were examined using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy. The forged 12Cr-MoVW steel samples exhibited parabolic behavior and a low oxidation rate compared with their as-cast counterparts. A protective oxide layer was uniformly formed at relatively low temperature (≤973 K) for the forged samples, which thus exhibited better oxidation resistance than the as-cast ones. These oxides are considered solid-solution compounds such as (Fe, Cr)2O3.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1099-1104
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recovery Of Electrodic Powder From Spent Lithium Ion Batteries (LIBs)
Odzysk proszku elektrodowego z zużytych akumulatorów litowo-jonowych
Autorzy:
Shin, S. M.
Jung, G. J.
Lee, W-J.
Kang, C. Y.
Wang, J. P.
Powiązania:
https://bibliotekanauki.pl/articles/354084.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
lithium ion battery
electrodic powder
cobalt
lithium
thermal treatment
bateria litowo-jonowa
proszek elektrodowy
kobalt
lit
obróbka termiczna
Opis:
This study was focused on recycling process newly proposed to recover electrodic powder enriched in cobalt (Co) and lithium (Li) from spent lithium ion battery. In addition, this new process was designed to prevent explosion of batteries during thermal treatment under inert atmosphere. Spent lithium ion batteries (LIBs) were heated over the range of 300°C to 600°C for 2 hours and each component was completely separated inside reactor after experiment. Electrodic powder was successfully recovered from bulk components containing several pieces of metals through sieving operation. The electrodic powder obtained was examined by X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS), and atomic absorption spectroscopy (AA) and furthermore image of the powder was taken by scanning electron microscopy (SEM). It was finally found that cobalt and lithium were mainly recovered to about 49 wt.% and 4 wt.% in electrodic powder, respectively.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1145-1149
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spontaneous Formation of Titanium Nitride on the Surface of a Ti Rod Induced by Electro-Discharge-Heat-Treatment in an N2 Atmosphere
Autorzy:
Lee, W. H.
Yoon, Y. H.
Kim, Y. H.
Lee, Y. K.
Kim, J. Y.
Chang, S. Y.
Powiązania:
https://bibliotekanauki.pl/articles/352477.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
titanium
surface modification
diffusion
heat treatment
XPS
Opis:
A single pulse of 2.0 to 3.5 kJ of input energy from a 450 mF capacitor was applied to a commercially pure Ti rod in a N2 atmosphere. The surface of the Ti rod transformed from TiO2 into titanium nitride in times as short as 159 msec, providing a bimodal morphology of the cross-section. A much higher value of hardness that was observed at the edge of the cross-section was attributed to nitrogen-induced solid-solution hardening that occurred during the electrical discharge process. The activation energy (Ea) for the diffusion process was estimated to be approximately 86.9 kJ/mol. Results show that the electrical discharge process is a possible potential method for the nitriding of Ti; advantages include a short processing time and control of the nitrided layer without dimensional changes.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1281-1285
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Pre-Sintering on the Diffusion Treatment of HRE for Coercivity Enhancement of a NdFeB Sintered Magnet
Autorzy:
Lee, M. W.
Lee, J. K.
Jang, T. S.
Powiązania:
https://bibliotekanauki.pl/articles/355250.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grain boundary diffusion process
GBDP
NdFeB magnet
coercivity
pre-sintering
Opis:
We investigated the effect of pre-sintering process on the penetration behavior of Dy in a NdFeB sintered magnet which was grain boundary diffusion treated with Cu/Al mixed Dy source. The pre-sintering of a magnet was performed at 900°C in vacuum and then the pre-sintered body was dipped in the solutions of DyH2, DyH2 + Cu, and DyH2 + Al, respectively. The dipped pre-sintered body were then fully sintered 4 hours at 1060°C followed by a subsequent annealing. The pre-sintering apparently improved the diffusivity of Dy atoms. The penetration of Dy into the magnet extended almost to 2,000 μm from the surface, about four times deeper than that of the normally sintered and diffusion treated one, when the DyH2 + Al solution was used as a Dy source. However, the resulting increase of coercivity was about 4 kOe, somewhat lower than that of the normally treated one, mostly due to excessive oxide formation that hindered to make a continuous Nd-rich grain boundary phase and a core-shell type structure.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 2; 597-601
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Consolidation Mechanism of Ti5Si3 Compact Obtained by Electro-Discharge-Sintering Directly from Physically Blended Ti-37.5 At.% Si Powder Mixture
Autorzy:
Chang, S. Y.
Cheon, Y. W.
Yoon, Y. H.
Kim, Y. H.
Kim, J. Y.
Lee, Y. K.
Lee, W. H.
Powiązania:
https://bibliotekanauki.pl/articles/353022.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sintering
mechanical alloying
powder consolidation
intermetallic compounds
titanium silicide
Opis:
Characteristics of electro-discharge-sintering of the Ti-37.5at.% Si powder mixture was investigated as a function of the input energy, capacitance, and discharge time without applying any external pressure. A solid bulk of Ti5Si3 was obtained only after in less than 129 μsec by the EDS process. During a discharge, the heat is generated to liquefy and alloy the particles, and which enhances the pinch pressure can condensate them without allowing a formation of pores. Three step processes for the self-consolidation mechanism during EDS are proposed; (a) a physical breakdown of oxide film on elemental as-received powder particles, (b) alloying and densifying the consolidation of powder particles by the pinch pressure, and (c) diffusion of impurities into the consolidated surface.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1299-1302
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Consolidation and Surface Modification of Mechanical Alloyed Ti-25.0 at.% Al Powder Mixture by Using an Electro-Discharge Technique
Autorzy:
Chang, S. Y.
Jang, H. S.
Yoon, Y. H.
Kim, Y. H.
Kim, J. Y.
Lee, Y. K.
Lee, W. H.
Powiązania:
https://bibliotekanauki.pl/articles/354212.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sintering
mechanical alloying
powder consolidation
intermetallic compounds
titanium aluminides
Opis:
Electrical discharges using a capacitance of 450 μF at 0.5, 1.0, and 1.5 kJ input energies were applied in a N2 atmosphere to obtain the mechanical alloyed Ti3Al powder without applying any external pressure. A solid bulk of nanostructured Ti3Al was obtained as short as 160 μsec by the Electrical discharge. At the same time, the surface has been modified into the form of Ti and Al nitrides due to the diffusion process of nitrogen to the surface. The input energy was found to be the most important parameter to affect the formation of a solid core and surface chemistry of the compact.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1293-1297
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Self-Consolidation Mechanism Of Porous Ti-6Al-4V Implant Prototypes Produced By Electro-Discharge-Sintering Of Spherical Ti-6Al-4V Powders
Mechanizm autokonsolidacji prototypów porowatych implantów wytworzonych przez spiekanie sferycznych proszków Ti-6Al-4V
Autorzy:
Lee, W. H.
Jo, Y. J.
Kim, Y. H.
Jo, Y. H.
Seong, J. G.
Van Tyne, C. J.
Chang, S. Y.
Powiązania:
https://bibliotekanauki.pl/articles/356277.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Ti-6Al-4V
implant
porous
sintering
electrodischarge
porowatość
spiekanie
proszki spiekane
Opis:
Electro-Discharge-Sintering (EDS) was employed to fabricate Ti-6Al-4V porous implant prototypes from atomized powders (100 – 150 μm), that were subjected to discharges of 0.75 to 2.0 kJ/0.7g-powder from 150, 300, and 450 μF capacitors. Both fully porous and porous-surfaced Ti-6Al-4V compacts with various solid core sizes were self-consolidated in less than 86 – 155 μsec. It is known that EDS can simultaneously produce the pinch pressure to squeeze and deform powder particles and the heat to weld them together. The formation of a solid core in these prototypes depends on the amounts of both the pinch pressure and heat generated during a discharge. The size of the solid core and the thickness of the porous layer can be successfully controlled by manipulating the discharge conditions such as input energy and capacitance.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1185-1189
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
System Identification from Multiple-Trial Data Corrupted by Non-Repeating Periodic Disturbances
Autorzy:
Phan, M. Q.
Longman, R. W.
Lee, S. C.
Lee, J. W.
Powiązania:
https://bibliotekanauki.pl/articles/908209.pdf
Data publikacji:
2003
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
automatyka
robotyka
system identification
disturbance identification
iterative learning control
repetitive control
interaction matrix
Opis:
Iterative learning and repetitive control aim to eliminate the effect of unwanted disturbances over repeated trials or cycles. The disturbance-free system model, if known, can be used in a model-based iterative learning or repetitive control system to eliminate the unwanted disturbances. In the case of periodic disturbances, although the unknown disturbance frequencies may be the same from trial to trial, the disturbance amplitudes, phases, and biases do not necessarily repeat. Furthermore, the system may not return to the same initial state at the end of each trial before starting the next trial. In spite of these constraints, this paper shows how to identify the system disturbance-free dynamics from disturbance-corrupted input-output data collected over multiple trials without having to measure the disturbances directly. The system disturbance-free model can then be used to identify the disturbances as well, for use in learning or repetitive control. This paper represents the first extension of the interaction matrix approach to the multiple-trial environment of iterative learning control.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2003, 13, 2; 185-192
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł

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