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    Wyświetlanie 1-48 z 48
    Tytuł:
    On the power-series expansion of a rational function
    Autorzy:
    Lee, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/1391914.pdf
    Data publikacji:
    1992
    Wydawca:
    Polska Akademia Nauk. Instytut Matematyczny PAN
    Opis:
    Introduction. The problem of determining the formula for $P_S(n)$, the number of partitions of an integer into elements of a finite set S, that is, the number of solutions in non-negative integers, $h_{s₁},..., h_{s_k}$, of the equation h_{s₁} s₁ + ... + h_{s_k} s_k = n,
    was solved in the nineteenth century (see Sylvester [4] and Glaisher [3] for detailed accounts). The solution is the coefficient of$xⁿ in [(1-x^{s₁})... (1-x^{s_k})]^{-1}, expressions for which they derived. Wright [5] indicated a simpler method by which to find part of the solution (at least in the case $s_i=i$). The current paper gives a simple method by which the power-series expansion of a rational function may be derived. Lemma 1 is well known and gives the general form of the solution. Lemma 2 is also well known. See, for example, Andrews [1], Example 2, p. 98. Lemma 3 shows how the recurrence relation of Lemma 2 becomes of bounded degree in certain cases. The recurrence relation is then solved, and the solution is extended from these certain cases to all cases. We then apply the result to investigate the growth of the difference $P_S(n) - P_T(n)$, where S and T are finite sets, and in particular when this difference is bounded. The differences $P_S^{(0)}(n) - P_T^{(0)}(n)$ and $P_S^{(1)}(n) - P_T^{(1)}(n)$ are also considered, where $P_S^{(0)}$ (resp. $P_S^{(1)}$) denotes the number of partitions of n into elements of S with an even (resp. odd) number of parts.
    Źródło:
    Acta Arithmetica; 1992, 62, 3; 229-255
    0065-1036
    Pojawia się w:
    Acta Arithmetica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Late Ordovician trilobites from the Xiazhen Formation in Zhuzhai, Jiangxi Province, China
    Autorzy:
    Lee, D.-C.
    Powiązania:
    https://bibliotekanauki.pl/articles/20075.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Opis:
    Trilobites from mudstone of the Upper Ordovician Xiazhen Formation of South China are described. The reef−associated, unique fauna comprises 25 species, 14 genera, and ten families. Five new species are named: Remopleurides xiazhenensis sp. nov., Hibbertia aodiensissp. nov., Vietnamia yushanensissp. nov., Ceraurinus zhuzhaiensissp. nov., and Pliomerina tashanensis sp. nov. The paucity of trilobites in reef−associated carbonates is interpreted that the trilobites diversified after the reef system decimated. Compared to the Late Ordovician trilobite faunas in other areas of South China, the Xiazhen mudstone fauna is unique in that the phacopids including Vietnamia, Ceraurinus, and Pliomerina account for 75% of the specimens collected. The occurrence of the same trilobite assemblage at different sampling localities along the dip direction of the formation suggests that the outcrops may be overlapped due to structural movement. The Xiazhen trilobite fauna is unique among the Late Ordovician fauna in that it is predominated by phacopids and associated with reef.
    Źródło:
    Acta Palaeontologica Polonica; 2013, 58, 4
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Godunov-type algorithms for numerical modeling of solar plasma
    Autorzy:
    Murawski, K.
    Lee, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/206269.pdf
    Data publikacji:
    2012
    Wydawca:
    Polska Akademia Nauk. Instytut Badań Systemowych PAN
    Tematy:
    computer science
    modelling
    numerical methods
    hyperbolic equations
    Opis:
    We discuss numerical methods to solve the Cauchy problem for hyperbolic equations, paying attention to equations which describe physical phenomena in fluid dynamics. We concentrate on Godunov-type methods which adopt Riemann solvers. These methods constitute a formidable task due to complexity of hyperbolic equations. Despite this complexity we show that the Godunov-type methods can be successfully applied to simulate complex systems such as described by equations of magnetohydrodynamics. In particular, we simulate thermal mode in a two-dimensional x-point magnetic field topology that is embedded in a gravitationally stratified solar atmosphere.
    Źródło:
    Control and Cybernetics; 2012, 41, 1; 35-56
    0324-8569
    Pojawia się w:
    Control and Cybernetics
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical methods of solving equations of hydrodynamics from perspectives of the code FLASH
    Autorzy:
    Murawski, K.
    Lee, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/202336.pdf
    Data publikacji:
    2011
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    numerical methods for hyperbolic equations
    finite volume method
    Godunov-type methods
    Opis:
    In this paper we review numerical methods for hydrodynamic equations. Internal complexity make numerical solutions of these equations a formidable task. We present results of advanced numerical simulations for a complex system with a use of a publicly available code, FLASH. These results proof that the numerical methods cope very well with this task.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 1; 81-91
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Molding Condition on Waviness Profile of GFRP Composites in Compression Molding
    Autorzy:
    Kim, J.
    Kim, H.
    Lee, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/1399878.pdf
    Data publikacji:
    2013-02
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.05.Lg
    81.05.Qk
    88.30.mj
    Opis:
    During compression molding of glass fiber reinforced plastic composites, annealing and quenching experiment is conducted by changing pre-heating and cooling method. As results, major cause of unevenness that affects waviness profile (winding) is the shrinkage of matrix during holding and cooling process. Waviness profile of the surface on molding in glass fiber reinforced plastic composites will be lower when holding pressure load is higher, mold temperature is lower during demolding, and cooling rate is slower. In addition, surface roughness of moldings is depending on holding pressure load compared with mold temperature. According to molding condition of glass fiber reinforced plastic composites, waviness profile of surface can be quantitatively estimated using the proposed equation.
    Źródło:
    Acta Physica Polonica A; 2013, 123, 2; 337-340
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Phase Transformation And Mechanical Properties Of Ti-12.1Mo-1Fe Alloy With Nano-Sized Precipitation
    Przemiany fazowe i właściwości mechaniczne stopu Ti-12.1Mo-1Fe z nanometrycznymi wydzieleniami
    Autorzy:
    Lee, D.-G.
    Seo, J.
    Li, Ch.
    Lee, Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/352551.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    age hardening
    Omega phase
    Ti-Mo-Fe alloy
    precipitation
    hartowanie
    faza omega
    stop Ti-Mo-Fe
    wydzielenia
    Opis:
    Microstructural characterization and aging hardening behaviors of a new designed Ti-12.1Mo-1Fe alloy during solution treatment and aging were investigated in the present study. It is well known that when β-Ti alloys are generally under solution treatment or aging, α phases and ω phases appear or disappear dependent on heat treatment temperature and holding time. It is very necessary to understand the phase transformation phenomenon and to control the microstructure because these phases can control the drastic changes of the mechanical and physical properties of these alloys. According to the calculated [Mo]eq value and the microstructural observation, the β-transus temperature was about 780°. After the solution treatment, this alloy was composed of the β-phase and the microstructure mainly consisted of the equiaxed β grains with the average size of 25 μm. ω phases which were precipitated during aging process, played a more important role to the hardening effect than α phases. The highest hardness value of Ti-12.1Mo-1Fe alloy showed in the condition of the aging temperature of 450°. The hardening due to ω-phase precipitation can lead to a high hardness about 480 Hv but the coarse α-phase result in hardness below 300 Hv.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1393-1396
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Development of a high-speed air bearing spindle
    Autorzy:
    Ha, Y.-H.
    Lee, D.-W.
    Hwang, Y.-K.
    Lee, C.-M.
    Powiązania:
    https://bibliotekanauki.pl/articles/1429126.pdf
    Data publikacji:
    2008
    Wydawca:
    Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
    Tematy:
    aerostatic bearing
    metal foam
    porous thrust bearing
    porous radial bearing
    Opis:
    This paper investigates an air spindle with both radial and thrust air bearings of newly developing one-directional porous materials. At present, orifice type and porous type are adopted for thrust air bearings. Orifice type thrust air bearing is fabricated by machining several micro-holes on a bearing pad bearing, permeability significantly affected by particle size and machining conditions is an important factor of performance, but it is hard to c porosities is suggested. It has many micro-porosities through axial direction, so stable and plenty of air can be supplied to the thrust bearing pad. A radial air bearing also can be substituted by a radial direction porous bearing as the same reason. In case of driving parts, built-in motor type is widely applied. But it needs additional cooling parts to drop heat from a motor. So application of an air turbine drive with light-weight shaft is suggested and additionally it will reduce fabricating cost.
    Źródło:
    Journal of Machine Engineering; 2008, 8, 4; 25-31
    1895-7595
    2391-8071
    Pojawia się w:
    Journal of Machine Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characteristics Of The Porous Body Sintered By Nano-Sized Fe-Cr-Al Alloy Powder
    Charakterystyka porowatego korpusu spiekanego z nanometrycznego proszku stopu Fe-Cr-Al
    Autorzy:
    Lee, S.-I.
    Lee, S.-H.
    Gu, B.-U.
    Lee, D.-W.
    Kim, B.-K.
    Powiązania:
    https://bibliotekanauki.pl/articles/356635.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Fe-Cr-Al powder
    metallic sponges
    sintering temperature
    oxidation resistance
    proszek Fe-Cr-Al
    proszek nanometryczny
    temperatura spiekania
    odporność na utlenianie
    Opis:
    Porous metal with uniform honeycomb structure was successfully produced by sintering using Fe-Cr-Al nano powder, which was prepared by the pulsed wire evaporation (PWE) in ethanol. Its process consisted of the several steps; 1) coating on the surface of polyurethane sponge with the liquid droplets generated from the ethanol-based slurry where the Fe-Cr-Al nano powders were uniformly dispersed, 2) heat treatment of debinding to remove the polyurethane sponge and 3) sintering of the porous green body formed by Fe-Cr-Al nano powders. The strut thickness of porous Fe-Cr-Al was increased by the increase of spraying times in ESP step. Also, The shrinkages and the oxidation resistance of the sintered porous body was increased with increase of sintering temperature. The optimal sintering temperature was shown to 1450°C in views to maximize the oxidation resistance and sinterability.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1275-1279
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    A Study On The Fabrication Of Iron Powder From Forging Scale Using Hydrogen
    Próby wytwarzanie proszku żelaza metodą redukcji zgorzeliny pochodzącej z procesów kucia za pomocą wodoru
    Autorzy:
    Shin, S. M.
    Lee, D.-W.
    Yun, J.-Y.
    Kang, Ch.-Y.
    Wang, J.-P.
    Powiązania:
    https://bibliotekanauki.pl/articles/350946.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    forging scale
    hydrogen partial pressure
    hematite
    iron powder
    kucie za pomocą wodoru
    hematyt
    redukcja zgorzeliny
    proszek żelaza
    Opis:
    This study was conducted to investigate the effect of hydrogen content, temperature, reaction time for the reduction of forging scale which is mainly composed of hematite (Fe2O3). All reductive reactions were performed over the temperature range of 700 to 1200°C as well as 0.1 to 1 atm of hydrogen partial pressures. The results showed that the mechanism for the reduction of iron oxides using hydrogen gas was not a simple process, but proceeded in multiple reduction stages thermodynamically. The iron oxide was almost completely reduced to metallic iron powder with 91 wt.% of iron content in the forging scale at 0.1 atm of hydrogen partial pressure. The content of iron was however found to be increased with increasing hydrogen partial pressure from 0.1 to 1 atm with regardless of temperatures. The metallic iron powder was obtained with the mean size of 100 μm and more porous structure was observed.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1547-1549
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Characterization of Cu and Ni Nano-Fluids Synthesized by Pulsed Wire Evaporation Method
    Autorzy:
    Kim, H.-S.
    Yilmaz, F.
    Dharmaiah, P.
    Lee, D.-J
    Lee, T.-H.
    Hong, S.-J.
    Powiązania:
    https://bibliotekanauki.pl/articles/356475.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    pulsed wire evaporation
    nanofluid
    Cu
    Ni
    suspension stability
    dispersibility
    Opis:
    In the present work, Cu and Ni nanofluids were synthesized using the pulsed wire evaporation (PWE) method in the different aqueous medias, namely (ethanol and ethylene glycol), and the effects of the aqueous media on the dispersion state, stability, and particle size of nanoparticles were studied. The size and morphology of synthesized nano-particles were investigated by transmission electron microscopy (TEM). Also, the dispersion stability of the nanofluids was evaluated by turbiscan analysis. The TEM results showed that the nano-particles were spherical in shape, and the average particle size was below 100 nm. The average particle size of the Cu nano-particles was smaller than that of Ni, which was attributed to a difference in the specific sublimation energy of the elements. Moreover, ethylene glycol (EG) exhibited higher suspension stability than ethanol. Finally, the dispersion stability of Cu@EG displayed the highest value due to lower particle size and greater viscosity.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 999-1004
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Growth and Characterization of Indium-Doped Zinc Oxide Thin Films Prepared by Sol-Gel Method
    Autorzy:
    Kim, M.
    Yim, K.
    Kim, S.
    Nam, G.
    Lee, D.
    Kim, Jin
    Kim, Jong
    Leem, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1491351.pdf
    Data publikacji:
    2012-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.05.Dz
    81.20.Fw
    78.66.Hf
    Opis:
    Indium-doped ZnO thin films were deposited by sol-gel spin-coating method with various In content. The effects of In content on the structural and optical properties of the indium-doped ZnO thin films were investigated by scanning electron microscopy, X-ray diffraction, and UV-visible spectroscopy. The particle-like surface morphology and the crystallinity of the indium-doped ZnO thin films were affected by change in the In content, especially at the In content of 3 at.%. The values of direct band gap were decreased with increase in the In content. The width of localized states in the optical band gap of the indium-doped ZnO thin films were changed with In content and the Urbach energy $(E_{U})$ was changed inversely with optical band gap of the indium-doped ZnO thin films.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 1; 217-220
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    ZnO Nanorods on Nanofibrous ZnO Seed Layers by Hydrothermal Method and Their Annealing Effects
    Autorzy:
    Yim, K.
    Jeon, S.
    Kim, M.
    Kim, S.
    Nam, G.
    Lee, D.
    Kim, Jin
    Kim, Jong
    Leem, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1491348.pdf
    Data publikacji:
    2012-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.05.Dz
    81.15.Lm
    78.55.Et
    Opis:
    ZnO nanorods were grown by using the hydrothermal method on p-type Si (100) substrates with nanofibrous ZnO seed layers. Before the ZnO nanorods growth, nanofibrous ZnO seed layers were spin-coated onto the Si substrates. The structural and optical properties of ZnO nanorods were characterized by scanning electron microscopy, X-ray diffraction, and photoluminescence. The fibrous ZnO nanorods is possible due to the surface morphology of the nanofibrous ZnO seed layers. To investigate annealing effects of the ZnO nanorods, the post-annealing process was carried out at various temperatures ranging from 300 to 700C under argon conditions. The structural and optical properties of the ZnO nanorods were also affected by the post-annealing treatment.
    Źródło:
    Acta Physica Polonica A; 2012, 121, 1; 214-216
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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
    Artykuł
    Tytuł:
    A stepwise ISO-based TQM implementation approach using ISO 9001:2015
    Autorzy:
    Chen, C.-K.
    Anchecta, K.
    Lee, J. -D.
    Dahlgaard, J. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/407353.pdf
    Data publikacji:
    2016
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Total Quality Management
    TQM
    ISO QMS
    ISO 9000
    ISO 9001:2015
    international standard
    Opis:
    The lack of an implementation roadmap always deters enterprises from choosing Total Quality Management (TQM) as its major management approach. This paper proposes a stepwise ISO-based TQM implementation approach which is based on the notion of the new threedimensional overall business excellence framework developed by Dahlgaard et al. [1]. The proposed approach consists of nine steps comprising three categories: “TQM faith building”, “TQM tools and techniques learning”, and “system development”. The steps in each of the three categories are arranged to span across the proposed nine-step approach. The ISO 9001:2015 standard is used as a case study to demonstrate the proposed approach. The ideas and benefits of the proposed approach are further discussed in relation to this illustration.
    Źródło:
    Management and Production Engineering Review; 2016, 7, 4; 65-75
    2080-8208
    2082-1344
    Pojawia się w:
    Management and Production Engineering Review
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    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
    Artykuł
    Tytuł:
    Large-Area Sodium Titanate Nanorods Formed On Titanium Surface Via NaOH Alkali Treatment
    Wielkopowierzchniowe nanopręty tlenku tytanu sodu wytworzone na powierzchni tytanu pod wpływem NaOH
    Autorzy:
    Lee, K.
    Yoo, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/354441.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    sodium titanate
    nanorods
    alkali treatment
    SEM
    tytanian sodu
    nanopręty
    obróbka alkaliczna
    Opis:
    Ti surfaces covered with large sodium titanate nanorods act as efficient electrodes for energy conversion and environmental applications. In this study, sodium titanate nanorod films were prepared on a Ti substrate in a 5M NaOH aqueous solution followed by heat treatment. The morphological characterization and the crystal structures of the sodium titanate nanorods were investigated via scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Thin amorphous sodium titanate layers formed during the alkali-treatment, and sodium titanate nanorods were obtained after heat treatment at a temperature of 700°C. The sodium titanate nanorods obtained at this temperature had a thickness of about 80 nm and a length of 1 μm. The crystal structure of the sodium titanate was identified with the use of Na2Ti5O11. The nanorods were agglomerated at a temperature above 900°C, and large-scale nanorods formed on the Ti surface, which may be used for electrodes for energy conversion applications.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1371-1374
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Compressive Deformation Behavior of Thick Micro-Alloyed HSLA Steel Plates at Elevated Temperatures
    Autorzy:
    Lee, J.-H.
    Kim, D.-O.
    Lee, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/351774.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    alloys
    rolling
    strain rate
    compression test
    HSLA steel
    Opis:
    The hot deformation behavior of a heavy micro-alloyed high-strength low-alloy (HSLA) steel plate was studied by performing compression tests at elevated temperatures. The hot compression tests were carried out at temperatures from 923 K to 1,223 K with strain rates of 0.002 s-1 and 1.0 s-1. A long plateau region appeared for the 0.002 s-1 strain rate, and this was found to be an effect of the balancing between softening and hardening during deformation. For the 1.0 s-1 strain rate, the flow stress gradually increased after the yield point. The temperature and the strain rate-dependent parameters, such as the strain hardening coefficient (n), strength constant (K), and activation energy (Q), obtained from the flow stress curves were applied to the power law of plastic deformation. The constitutive model for flow stress can be expressed as σ = (39.8 ln (Z) – 716.6) · ε(−0.00955ln(Z) + 0.4930) for the 1.0 s-1 strain rate and σ = (19.9ln (Z) – 592.3) · ε(−0.00212ln(Z) + 0.1540) for the 0.002 s-1 strain rate.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1191-1196
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Boundary element modelling of wave diffraction by interaction with wave-offshore structure and dredged region
    Autorzy:
    Kim, S. D.
    Lee, H. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/259525.pdf
    Data publikacji:
    2010
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    Submarine pit
    Green function
    boundary integral approach
    breakwater
    Opis:
    The purpose of this study is to estimate the wave height at the front face of breakwater (Refracted breakwater and Straight breakwater), when dredging like the submarine pit is performed in the distant offshore from outer breakwater. The wave field of the problem is considered to be two dimensional planes and the configuration of the pit region is designated by a single horizontal long-rectangular system. The numerical approach uses the Green function based on the boundary integral approach. The results of the present numerical works are illustrated by applying the normal and inclined incidence. It is shown that in the case of normal incidence, the ratio of wave height reduction at the front face of both types of breakwaters is approximately more than 20% due to the effect of the submarine pit on the sea bed. Furthermore, regardless of the type of breakwater and the difference in incident wave angles, the ratio of wave height was shown to be reduced.
    Źródło:
    Polish Maritime Research; 2010, 2; 67-71
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Design of simultaneous input-shaping-based SIRMs fuzzy control for double-pendulum-type overhead cranes
    Autorzy:
    Qian, D.
    Tong, S.
    Yang, B.
    Lee, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/953059.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    SIRMs fuzzy control
    double-pendulum-type overhead cranes
    sterowanie rozmyte
    SIRM
    suwnica wahadłowa
    Opis:
    Overhead cranes are extensively employed but their performance suffers from the natural sway of payloads. Sometime, the sway exhibits double-pendulum motions. To suppress the motions, this paper investigates the design of simultaneous input-shaping-based fuzzy control for double-pendulum-type overhead cranes. The fuzzy control method is based on the single input-rule modules (SIRMs). Provided the all the system variables are measurable, the SIRMs fuzzy controller is designed at first. To improve the performance of the fuzzy controller, the simultaneous input shaper is adopted to shape the control command generated by the fuzzy controller. Compared with other two control methods, i.e., the SIRMs fuzzy control and the convolved input-shaping-based SIRMs fuzzy control, simulation results illustrate the feasibility, validity and robustness of the presented control method for the anti-swing control problem of double-pendulum-type overhead cranes.
    Źródło:
    Bulletin of the Polish Academy of Sciences. Technical Sciences; 2015, 63, 4; 887-896
    0239-7528
    Pojawia się w:
    Bulletin of the Polish Academy of Sciences. Technical Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Point-Contact Spectroscopy of Superconducting $MgCNi_3$ Single Crystals
    Autorzy:
    Pribulová, Z.
    Szabó, P.
    Kačmarčík, J.
    Samuely, P.
    Jang, D.
    Lee, H.
    Lee, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1813611.pdf
    Data publikacji:
    2008-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.50.+r
    Opis:
    The first point-contact spectroscopy measurements on $MgCNi_3$ single crystals of very good quality are presented. The measurements have been performed in the temperature range from 1.5 K up to 10 K and at magnetic fields up to 6 T. The superconducting energy gap Δ of the system is found to be scattered between 1 and 1.2 meV which gives the 2Δ/k $T_c$ ratio between BCS weak-coupling value of ~3.5 and a strong coupling of about 4.2. The excess current evaluated in magnetic field indicates the presence of a single energy gap.
    Źródło:
    Acta Physica Polonica A; 2008, 113, 1; 215-218
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Contamination of soil with heavy metals drained out from abandoned mines in the South-West region of Korea
    Autorzy:
    Kim, S.-D.
    Dho, H.-S.
    Lee, S.-J.
    Powiązania:
    https://bibliotekanauki.pl/articles/207493.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    soil pollution
    abandoned mines
    arsenic
    heavy metals
    nickel
    soils
    zinc
    contamination level
    forest regions
    surface soil
    zanieczyszczenie gleby
    zlikwidowane kopalnie
    arsen
    metale ciężkie
    nikiel
    gleby
    cynk
    poziom zanieczyszczeń
    obszary leśne
    powierzchniowe warstwy gleby
    Opis:
    Contamination of soil with heavy metals drained out from twenty eight abandoned mines in the southwest regions of Korea has been investigated. Utilizing various statistical techniques, the goal was to evaluate and analyze pH and the contamination with Arsenic, and the following six heavy metals: cadmium, hydrargyrum, lead, nickel, chromium, and zinc. Contamination levels of heavy metals were determined depending on the depth of the soil. Results indicated that the subsoil and the surface soil both were strongly contaminated with lead and arsenic. Furthermore, the subsoil also contained much nickel. In forest regions, high levels of lead and arsenic, whereas in all regions high levels of zinc have been detected.
    Źródło:
    Environment Protection Engineering; 2015, 41, 3; 61-72
    0324-8828
    Pojawia się w:
    Environment Protection Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fabrication of Mo-Si-B Intermetallic Compound Powders Under Different Heat Treatment Conditions
    Autorzy:
    Park, J. H.
    Lee, S.
    Kim, D.
    Kim, Y.
    Yang, S. H.
    Lee, S. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/353369.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Mo-Si-B alloys
    intermetallic compounds
    reitveld refinement
    T2 phase
    A15 phase
    Opis:
    In this research, we investigated the effects of reduction atmospheres on the creation of the Mo-Si-B intermetallic compounds (IMC) during the heat treatments. For outstanding anti-oxidation and elevated mechanical strength at the ultrahigh temperature, we fabricated the uniformly dispersed IMC powders such as Mo5SiB2 (T2) and Mo3Si (A15) phases using the two steps of chemical reactions. Especially, in the second procedure, we studied the influence of the atmospheres (e.g. vacuum, argon, and hydrogen) on the synthesis of IMCs during the reduction. Furthermore, the newly produced IMCs were observed by SEM, XRD, and EDS to identify the phase of the compounds. We also calculated an amount of IMCs in the reduced powders depending on the atmosphere using the Reitveld refinement method. Consequently, it is found that hydrogen atmosphere was suitable for fabrication of IMC without other IMC phases.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 3; 1509-1512
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Towards Safe Navigation by Formalizing Navigation Rules
    Autorzy:
    Kreutzmann, A.
    Wolter, D.
    Dylla, F.
    Lee, J. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/117627.pdf
    Data publikacji:
    2013
    Wydawca:
    Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
    Tematy:
    safety of navigation
    Navigation Rules
    artificial intelligence
    Spatio-temporal Logics
    Opis:
    One crucial aspect of safe navigation is to obey all navigation regulations applicable, in particular the collision regulations issued by the International Maritime Organization (IMO Colregs). Therefore, decision support systems for navigation need to respect Colregs and this feature should be verifiably correct. We tackle compliancy of navigation regulations from a perspective of software verification. One common approach is to use formal logic, but it requires to bridge a wide gap between navigation concepts and simple logic. We introduce a novel domain specification language based on a spatio‐temporal logic that allows us to overcome this gap. We are able to capture complex navigation concepts in an easily comprehensible representation that can directly be utilized by various bridge systems and that allows for software verification.
    Źródło:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2013, 7, 2; 161-168
    2083-6473
    2083-6481
    Pojawia się w:
    TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Aluminum Oxide Formation On Fecral Catalyst Support By Electro-Chemical Coating
    Powstawanie tlenku glinu na nośniku katalizatora FeCrAl przez osadzanie elektrochemiczne
    Autorzy:
    Yang, H. S.
    Jang, D. H.
    Lee, K. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/355942.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    FeCrAl
    catalyst support
    aluminum oxide formation
    PEO
    plasma electrolytic oxidation
    electrochemical coating
    nośnik katalizatora
    tlenek glinu
    plazmowe utlenianie elektrolityczne
    elektrochemiczne osadzanie
    Opis:
    FeCrAl is comprised essentially of Fe, Cr, Al and generally considered as metallic substrates for catalyst support because of its advantage in the high-temperature corrosion resistance, high mechanical strength, and ductility. Oxidation film and its adhesion on FeCrAl surface with aluminum are important for catalyst life. Therefore various appropriate surface treatments such as thermal oxidation, Sol, PVD, CVD has studied. In this research, PEO (plasma electrolytic oxidation) process was applied to form the aluminum oxide on FeCrAl surface, and the formed oxide particle according to process conditions such as electric energy and oxidation time were investigated. Microstructure and aluminum oxide particle on FeCrAl surface after PEO process was observed by FE-SEM and EDS with element mapping analysis. The study presents possibility of aluminum oxide formation by electro-chemical coating process without any pretreatment of FeCrAl.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1503-1506
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    AC Microcalorimetry of Superconducting $MgCNi_3$ Single Crystals
    Autorzy:
    Kačmarčík, J.
    Pribulová, Z.
    Samuely, P.
    Marcenat, C.
    Klein, T.
    Jang, D.
    Lee, H.
    Lee, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/1813689.pdf
    Data publikacji:
    2008-01
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.70.Ad
    74.25.Bt
    Opis:
    The low-temperature specific heat of single-crystal samples of superconducting $MgCNi_3$ with typical dimensions 200 μm were measured for the first time. A computer controlled ac microcalorimeter using an optical fiber and an infrared light-emitting diode as the heat source was used down to 2 K at magnetic fields up to 8 T. The specific heat data suggest a moderate coupling in $MgCNi_3$.
    Źródło:
    Acta Physica Polonica A; 2008, 113, 1; 363-366
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Premixed combustion of acetylene-hydrogen fuel mixtures for thermodynamic state generation in a constant volume combustion vessel
    Autorzy:
    Johnson, S.
    Nesbitt, J.
    Lee, S. -Y.
    Naber, J. D.
    Powiązania:
    https://bibliotekanauki.pl/articles/242374.pdf
    Data publikacji:
    2009
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    combustion engine
    diesel engine
    combustion processes
    pressure vessel
    preborn
    Opis:
    Flammability limits and flame speeds of dilute-lean fuel mixtures of hydrogen (H2) and acetylem premixed with oxygen (02) and nitrogen (N2) were examined with a detailed kinetics model. These mixtures are used in a preburn in a constant volume combustion vessel to create elevated temperatures and pressures with gas compositions that represent the thermodynamic state in a diesel engine combustion chamber at fuel injection and auto ignition. A mixture of hydrogen and acetylene with combined atomic hydrogen to carbon ratio (HCR) of 1.85 was used to match that of typical diesel fuel and results are shown in comparison to a previously used mixture with a HCR of 1.17. The lower flammability limit (LFL) of the HCR 1.85 fuel mixture was found at an equivalence ratio of 0.235, while flame speed and adiabatic combustion temperatures were also predicted for post preburn product oxygen levels between O and 21 percent. Flame speeds were shown to decrease with a reduction in oxygen concentration, an increase in nitrogen dilution, while combustion temperatures increased over most of this range. Trends for this relation of flame speed and temperature are presented and a new premixed fuel mixture with an HCR of 1.85 is proposed.
    Źródło:
    Journal of KONES; 2009, 16, 2; 199-208
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Structure, morphology, and band gap of Ti-V-O mixed oxides processed by coprecipitation and calcination
    Autorzy:
    Park, M.
    Lim, Y.
    Sung, Y.
    Kwak, D.
    Lee, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1061893.pdf
    Data publikacji:
    2016-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.05.Hd
    Opis:
    Mixed oxides of Ti-V-O were co-precipitated by wet process using TiCl₄ and VOCl₃ as starting materials. As-precipitated gels were calcinated at 800°C for 4 hours in oxygen atmosphere. Effects of vanadium content on the structural evolution, morphology, and band gap of Ti-V-O oxides were investigated. Calcination has produced mixtures of TiO₂/VO₂/V₂O₅ oxides and has allowed formation of Ti_{1-x}V_{x}O₂. Lattice parameters of rutile TiO₂ were precisely measured to investigate vanadium substitution into single rutile phase of Ti_{1-x}V_{x}O₂ with varying vanadium content. As vanadium addition was increased, particles were coarsening rapidly during calcination. Band gap of the Ti-V-O oxides was measured using ultraviolet visible light spectrometer. A decrease of band gap down to 1.7 eV with the addition of maximum of 10 at.% of vanadium was measured, which is due to the formation of single phase of Ti_{1-x}V_{x}O₂ as well as the formation of metallic VO₂ or V₂O₅ particles.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 4; 875-877
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of the Calcination Temperature on the Optical and Mechanical Properties of Y2O3-MgO Nanocomposite
    Autorzy:
    Yong, S.-M.
    Choi, D. H.
    Lee, K.
    Ko, S.-Y.
    Cheong, D.-I.
    Powiązania:
    https://bibliotekanauki.pl/articles/351252.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    infrared transparent ceramics
    Y2O3-MgO nanocomposites
    sol-gel combustion synthesis
    calcination
    spark plasma sintering
    Opis:
    Y2O3-MgO nanocomposites are one of the most promising materials for hypersonic infrared windows and domes due to their excellent optical transmittance and mechanical properties. In this study, influence of the calcination temperature of Y2O3-MgO nanopowders on the microstructure, IR transmittance, and hardness of Y2O3-MgO nanocomposites was investigated. It was found that the calcination temperature is related to the presence of residual intergranular pores and grain size after spark plasma sintering. The nanopowders calcined at 1000°C exhibits the highest infrared transmittance (82.3% at 5.3 μm) and hardness (9.99 GPa). These findings indicated that initial particle size and distribution of the nanopowders are important factors determining the optical and mechanical performances of Y2O3-MgO nanocomposites.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 3; 1481-1484
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Microstructure of Small Amount of TM Added Al-Mg-Si Alloys with Two-Step Ageing
    Autorzy:
    Kuroda, Y.
    Yoshino, D.
    Lee, S.
    Ikeno, S.
    Matsuda, K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1032888.pdf
    Data publikacji:
    2017-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.40.Cd
    68.37.Lp
    Opis:
    Traditionally, Al-Mg-Si alloys are strengthened by dispersed small particles and they have medium strength with good formability. It is well known that alloying elements on Al-Mg-Si alloys (e.g. Cu) can improve mechanical properties because Cu can alter precipitation sequence. In this research, we investigated the effect of transition metals (TM) on Al-1.06at.%MgSi-TM alloys through single- and two-step ageing. Mechanical property and microstructure observation were conducted by micro Vickers hardness measurement and transmission electron microscopy.
    Źródło:
    Acta Physica Polonica A; 2017, 131, 5; 1373-1375
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect Of DyMn Alloy-Powder Addition On Microstructure And Magnetic Properties Of NdFeB Sintered Magnets
    Wpływ dodatku proszku DyMn na mikrostrukturę i właściwości magnetyczne spiekanych magnesów NdFeB
    Autorzy:
    Lee, M.-W.
    Dhakal, D. R.
    Kim, T. H.
    Lee, S. R.
    Kim, H. J.
    Jang, T. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/357010.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Nd-Fe-B sintered magnets
    DyMn-alloy powder
    coercivity
    low melting point element
    magnesy spiekane
    proszek DyMn
    koercja
    elementy o niskiej temperaturze topnienia
    Opis:
    Micostructural change and corresponding effect on coercivity of a NdFeB sintered magnet mixed with small amount of DyMn powder was investigated. In the sintered magnet mixed with the DyMn alloy-powder Dy-rich shell was formed at outer layer of the main grains, while Mn was mostly concentrated at Nd-rich triple junction phase (TJP), lowering melting temperature of the Nd-rich phase that eventually improved the microstructural characteristics of the gain boundary phase. The coercivity of a magnet increased more than 3.5 kOe by the mixing of the DyMn alloy-powder.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1407-1409
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Ni Content on the Austenite Stability and Mechanical Properties of Nanocrystalline Fe-Ni Alloy Fabricated by Spark Plasma Sintering
    Autorzy:
    Park, D.
    Oh, S.-J.
    Shon, I.-J.
    Lee, S.-J.
    Powiązania:
    https://bibliotekanauki.pl/articles/352972.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Fe-Ni alloy
    austenite stability
    mechanical properties
    spark plasma sintering
    Opis:
    The mechanical behavior and the change of retained austenite of nanocrystalline Fe-Ni alloy have been investigated by considering the effect of various Ni addition amount. The nanocrystalline Fe-Ni alloy samples were rapidly fabricated by spark plasma sintering (SPS). The SPS is a well-known effective sintering process with an extremely short densification time not only to reach a theoretical density value but also to prevent a grain growth, which could result in a nanocrystalline structures. The effect of Ni addition on the compressive stress-strain behavior was analyzed. The variation of the volume fraction of retained austenite due to deformation was quantitatively measured by means of x-ray diffraction and microscope analyses. The strain-induced martensite transformation was observed in Fe-Ni alloy. The different amount of Ni influenced the rate of the strain-induced martensite transformation kinetics and resulted in the change of the work hardening during the compressive deformation.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 3; 1477-1480
    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
    Tytuł:
    An analysis on the thermal characteristics according to the viscosity of bearing lubricant and the cooling condition for the high speed motor spindle
    Autorzy:
    Choi, D. B.
    Lee, J. J.
    Kim, S. T.
    Kwon, H. D.
    Kim, C. Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/1429194.pdf
    Data publikacji:
    2008
    Wydawca:
    Wrocławska Rada Federacji Stowarzyszeń Naukowo-Technicznych
    Tematy:
    high speed motor spindle
    thermal displacement cooling condition
    lubricant viscosity
    Opis:
    Thermal displacement of the high speed machine tools has a large influence on machining accuracy. The high speed motor spindle with many heat sources is widely used for the high speed machine tools recently. The important problem in this spindle is to reduce and minimize the thermal effects by motor and bearings. This paper presents the analysis on thermal characteristics for high speed motor spindle system with oil-air lubricated angular contact ceramic ball bearings and built-in motor. An analysis on the thermal characteristics of spindle is performed according to the cooling conditions and the viscosity of bearing lubricants by using finite element method. This results can be applied to the design and manufacturing for the high speed motor spindle.
    Źródło:
    Journal of Machine Engineering; 2008, 8, 4; 88-98
    1895-7595
    2391-8071
    Pojawia się w:
    Journal of Machine Engineering
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects Of Environmental Factors On The Dispersion Behavior Of Iron Oxide In Aqueous Solutions With Poly Acrylic Acid
    Wpływ parametrów charakteryzujących wodne roztwory poli(kwasu akrylowego) na dyspersję tlenku żelaza
    Autorzy:
    Lee, E.-H.
    Kim, K.-M.
    Maeng, W.-Y.
    Hur, D.-H.
    Powiązania:
    https://bibliotekanauki.pl/articles/354513.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    polyacrylic acid
    dispersion stability
    magnetite
    nanoparticles
    suspension
    poli(kwas akrylowy)
    stabilność dyspersji
    magnetyt
    nanocząstki
    zawiesina
    Opis:
    After preparing aqueous suspensions from magnetite particles with a poly-acrylic acid, we investigated the effects of several experimental parameters. We characterized the stability of the suspensions using visual inspection, sedimentation, adsorption, and thermal stability of the dispersant. The dispersion stability is affected by the solution pH, the concentrations of magnetite particles, the molecular weight, the concentration of the dispersants, and the temperature. The stability of the suspensions increased as the concentration of the dispersant and the temperature increased. In terms of the molecular weights of the dispersant, the suspensions with dispersant of low-molecular weight (1800) were more stable than those of high-molecular weight (250000) at room temperature. However, at high temperature the suspensions with high-molecular weight showed stability. The adsorption efficiency of the dispersant was very low. The dispersant of high-molecular weight showed a higher thermal integrity than that of low-molecular weight. From this work, we obtained the optimum conditions for stable aqueous suspensions of magnetite particles.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1561-1564
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Adaptive Predictive Control of a Distillation Column
    Autorzy:
    Yoon, T. W.
    Yang, D. R.
    Lee, K. S.
    Kwon, Y. M.
    Powiązania:
    https://bibliotekanauki.pl/articles/908309.pdf
    Data publikacji:
    1999
    Wydawca:
    Uniwersytet Zielonogórski. Oficyna Wydawnicza
    Tematy:
    adaptacyjny układ sterowania
    sterownik predykcyjny
    adaptive control
    multivariable predictive controller
    distillation column
    Opis:
    Distillation processes reveal complicated multivariable nonlinear dynamics for which it is difficult to design a high-performance control system. This paper proposes an adaptive control scheme for a distillation column. The proposed adaptive system consists of a multivariable receding-horizon predictive controller using a transfer function model and a recursive least-squares (RLS) based estimator. Simulations show a consistent closed-loop performance despite the uncertain nonlinear characteristics of the distillation column.
    Źródło:
    International Journal of Applied Mathematics and Computer Science; 1999, 9, 1; 193-206
    1641-876X
    2083-8492
    Pojawia się w:
    International Journal of Applied Mathematics and Computer Science
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Manufacturing and Macroscopic Properties of Y2O3 Coating Layer on Ceramic (AlN) Substrate Fabricated by Aerosol Deposition
    Autorzy:
    Wi, D.-Y.
    Ham, G.-S.
    Kim, S.-H.
    Lee, K.-A.
    Powiązania:
    https://bibliotekanauki.pl/articles/353052.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    aerosol deposition
    Y2O3 coating layer
    AlN matrix
    nano indentation
    Opis:
    This study attempted to manufacture an Y2O3 ceramic coating layer on a ceramic (AlN) substrate using aerosol deposition (AD) and investigated its macroscopic properties. Pure Y2O3 powder with a polygonal shape and average size of 5.0 μm was used as initial feedstock. Using aerosol deposition with suitable process conditions, an Y2O3 coating layer was successfully fabricated on aluminum nitride (AIN). The thickness of the manufactured coating layer was approximately 10 mm. The coating layer consisted of Y2O3 phase identical to that in the initial powder, and no additional oxides were identified. In regard to the roughness of the Y2O3 coating layer, the average roughness (Ra) measured 1.32 μm, indicating that the surface roughness was relatively even compared to the initial powder size (5 μm). Mechanical properties of the Y2O3 coating layer were measured using nano indentation equipment, and the indentation modulus of the Y2O3 coating layer fabricated by aerosol deposition measured 136.5 GPa. The interface of the coating layer was observed using TEM, and the deposition mechanism of the Y2O3 coating layer manufactured by aerosol deposition was also discussed.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 3; 1463-1466
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Development of a large beam facility
    Autorzy:
    Oh, B.
    In, S.
    Lee, K.
    Jeong, S.
    Seo, C.
    Chang, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/147420.pdf
    Data publikacji:
    2006
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    beam facility
    high power ion beam
    o neutral beam
    beam line component
    cryosorption pump
    Opis:
    A large beam facility for the application of high power ion beams has been developed at the Korea Atomic Energy Research Institute (KAERI). The primary usage of this facility is to develop an 8 MW neutral beam heating system for a tokamak, but other applications using a large beam would also be possible in the near future. The facility is composed of a bucket ion source (120 kV, 65 A), related beam line components including a large vacuum chamber (3 m x 4 m x 5 m), power supplies for the ion source, control and DAS (Data Acquisition System), beam diagnostics system, and a water circulation system (2 MW) for cooling of the beam line components. The maximum beam parameters at present are a beam energy of 87 kV and a beam current of 17.5 A with a beam size of 13 x 45 cm2. A maximum pulse length of 10 s could be achieved with a 1 MW beam power. The beam power with a hydrogen ion will be increased up to 7.5 MW during 5 s.
    Źródło:
    Nukleonika; 2006, 51, 1; 37-42
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Thermal Conductivity and Microstructure of Copper Coated Graphite Composite by Spark Plasma Sintering Process
    Autorzy:
    Park, S. H.
    Kim, D. B.
    Lee, R. G.
    Son, I. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/355632.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    metal matrix composites
    thermal conductivity
    thermal expansion
    interfacial bonding
    spark plasma sintering
    Opis:
    This study focuses on the fabrication of thermal management material for power electronics applications using graphite flake reinforced copper composites. The manufacturing route involved electroless plating of copper in the graphite flake and sintering process are optimized. The microstructures, interface, thermal properties, and relative density of graphite/Cu composites are investigated. The relative density of the composites shows 99.5% after sintering. Thermal conductivities and coefficients of thermal expansion of this composites were 400-480 Wm-1K-1 and 8 to 5 ppm k-1, respectively. Obtained graphite nanoplatelets-reinforced composites exhibit excellent thermo-physical properties to meet the heat dispersion and matching requirements of power electronic devices to the packaging materials.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1303-1306
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of Additives on the Densification Processes and Properties of Silica-Based CMCs
    Autorzy:
    Ko, S.-Y.
    Yong, S.-M.
    Lee, S. J.
    Cheong, D.-I.
    Baek, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/355134.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ceramic matrix composite
    CMC
    silica
    densification
    mechanical properties
    Opis:
    The effect of additives on the densification behavior and mechanical properties of pure and additive (Zr, B and Mg)-added silica ceramics were investigated for their application to the matrix phase of a silica fiber reinforced silica (SiO2 /SiO2f ) composite. The additives affected the rate of densification and crystallization (or transformation) of the amorphous silica. Among the compositions, pure silica ceramics sintered at 900°C for 1h showed the maximum flexural strength. Based on the results, SiO2 /SiO2f was fabricated by a repeated vacuum-assisted infiltration method followed by the heat treatment at 900°C for 1h. The relative density of the composite was 78.2% with a flexural strength of 22.4 MPa. Fractography revealed that the composite was damaged by strong bonding at the fiber/matrix interface and the fracture of fiber.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 3; 1485-1488
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    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:
    A New Deinonychosaurian Track from the Lower Cretaceous Hekou Group, Gansu Province, China
    Autorzy:
    Xing, L.
    Li, D.
    Harris, J.D.
    Bell, P.R.
    Azuma, Y.
    Fujita, M.
    Lee, Y.-N.
    Currie, P.J.
    Powiązania:
    https://bibliotekanauki.pl/articles/20547.pdf
    Data publikacji:
    2013
    Wydawca:
    Polska Akademia Nauk. Instytut Paleobiologii PAN
    Opis:
    Herein we describe deinonychosaurian (Dinosauria: Theropoda) tracks in the Lower Cretaceous Hekou Group at sites I and II of Liujiaxia Dinosaur National Geopark, Gansu Province, China. The site preserves 71 didactyl tracks, the largest concentration of deinonychosaurian tracks in Asia. The tracks pertain to a new dromaeopodid ichnospecies: Dromaeosauripus yongjingensis ichnosp. nov., which is diagnosed by: a digital pad formula of x−1−3−4−x and a mean divarication angle between digits III and IV of 19°, and having the proximal portion of digit II contacting the anterior margin of a large, rounded metatarsophalangeal pad. Six Dromaeosauripustrackways from site II comprise at least two, and possibly three, turning trackways in which the track maker(s) turned without slowing down. None of the Dromaeosauripus trackways are parallel or closely spaced, suggesting that they were made by solitary track makers. Estimates of dromaeopodid track−maker sizes are between 61–300 cm, well within the size range established by body fossils of both dromaeosaurids and troodontids.
    Źródło:
    Acta Palaeontologica Polonica; 2013, 58, 4
    0567-7920
    Pojawia się w:
    Acta Palaeontologica Polonica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Studies on the effect of coal particle size on biodepyritization of high sulfur coal in batch bioreactor
    Autorzy:
    Singh, S.
    Srichandan, H.
    Pathak, A.
    Gahan, Ch. S.
    Lee, S.
    Kim, D. J.
    Kim, B. G.
    Powiązania:
    https://bibliotekanauki.pl/articles/778523.pdf
    Data publikacji:
    2015
    Wydawca:
    Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
    Tematy:
    biodepyritization
    coal
    pyrite
    stirred tank bioreactor
    Opis:
    The moderate thermophilic mix culture bacteria were used to depyritize the Illinois coal of varying particle sizes (-100 μm, 100-200 μm, +200 μm). Mineral libration analysis showed the presence of pyrite along with other minerals in coal. Microbial depyritization of coal was carried out in stirred tank batch reactors in presence of an iron-free 9K medium. The results indicate that microbial depyritization of coal using moderate thermophiles is an efficient process. Moreover, particle size of coal is an important parameter which affects the efficiency of microbial depyritization process. At the end of the experiment, a maximum of 75% pyrite and 66% of pyritic sulphur were removed from the median particle size. The XRD analysis showed the absence of pyrite mineral in the treated coal sample. A good mass balance was also obtained with net loss of mass ranging from 5-9% showing the feasibility of the process for large scale applications.
    Źródło:
    Polish Journal of Chemical Technology; 2015, 17, 1; 97-102
    1509-8117
    1899-4741
    Pojawia się w:
    Polish Journal of Chemical Technology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Allometric scaling of marbofloxacin pharmacokinetics: a retrospective analysis
    Autorzy:
    Yohannes, S.
    Hossain, M.A.
    Kim, J.Y.
    Lee, S.J.
    Kwak, D.M.
    Suh, J.W.
    Park, S.C.
    Powiązania:
    https://bibliotekanauki.pl/articles/31939.pdf
    Data publikacji:
    2014
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Opis:
    The association between physiologically dependent pharmacokinetic parameters (CLB, T1/2β, Vdss) of marbofloxacin and body weight was studied in eight animal species based on allometric equation Y = aWb, where ‘Y’ is the pharmacokinetic parameter, ‘W’ is body weight, ‘a’ is allometric coefficient (intercept) and ‘b’ is the exponent that describes relation between pharmacokinetic parameter and body weight. The body clearance of marbofloxacin has shown significant (P<0.0001) relation with size (Bwt) in various animal species. However, half-life and volume of distribution were not in association with body weight. Although half-life and volume of distribution were not in a good correlation with body weight, statistically significant association between the body clearance and body weight suggests validity of allometric scaling for predicting pharmacokinetic parameters of marbofloxacin in animal species that have not been studied yet. However further study considering large sample size and other parameters influencing pharmacokinetics of marbofloxacin is recommended.
    Źródło:
    Polish Journal of Veterinary Sciences; 2014, 17, 1
    1505-1773
    Pojawia się w:
    Polish Journal of Veterinary Sciences
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Carbon Co-Deposition During Gas Reduction of Water-Atomized Fe-Cr-Mo Powder
    Autorzy:
    Ali, B.
    Choi, S. H.
    Seo, S. J.
    Maeng, D. Y.
    Lee, C. G.
    Kim, T. S.
    Park, K. T.
    Powiązania:
    https://bibliotekanauki.pl/articles/352709.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    water atomization
    Fe-based powder
    oxide reduction
    powder metallurgy
    sinter-hardening alloys
    Opis:
    The water atomization of iron powder with a composition of Fe-3Cr-0.5Mo (wt.%) at 1600°C and 150 bar creates an oxide layer, which in this study was reduced using a mixture of methane (CH4) and argon (Ar) gas. The lowest oxygen content was achieved with a 100 cc/min flow rate of CH4, but this also resulted in a co-deposition of carbon due to the cracking of CH4. This carbon can be used directly to create high-quality, sinter hardenable steel, thereby eliminating the need for an additional mixing step prior to sintering. An exponential relationship was found to exist between the CH4 gas flow rate and carbon content of the powder, meaning that its composition can be easily controlled to suit a variety of different applications.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1119-1124
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Oxidation Behavior of Steel with Cr Content and Water Flow Rate
    Autorzy:
    Kim, D.-J.
    Kim, K. M.
    Shin, J. H.
    Cheong, Y. M.
    Lee, E. H.
    Lee, G. G.
    Kim, S. W.
    Kim, H. P.
    Choi, M. J.
    Lim, Y. S.
    Hwang, S. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/351548.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    steel
    flow accelerated corrosion
    Cr content
    flow rate
    surface oxides
    Opis:
    Fast water flow facilitates ferrous ion transport leading to flow accelerated corrosion (FAC) of carbon steel and the possibility of a large accident through a failure of a secondary pipe in a nuclear power plant. Ion transport is directly linked to oxide properties such as the thickness, chemical composition and porosity. This work deals with a precise observation of the cross section of the corroded specimen focusing on an oxide passivity and its thickness using SEM (scanning electron microscope) and TEM (transmission electron microscope) as well as an apparent weight loss and a surface observation for the specimens corroded using a rotating cylindrical electrode autoclave system in pure water of pH 7 at 150°C having dissolved oxygen below 1 ppb within a flow rate range of 0 to 10 m/s. The Cr content in steel was changed from 0.02 to 2.4 wt%. Increasing the Cr content in the alloy, the FAC rate and oxide thickness decreased. The oxide porosity tends to decrease with the Cr content and immersion time owing to the development of Cr containing oxide. The oxidation behavior is not changed with the immersion time.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1383-1387
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Chiny, Stany Zjednoczone i świat w oczach Wielkiego Mistrza Lee Kuan Yewa
    Lee Kuan Yew : the grand masters insights on China, the United States, and the world
    Autorzy:
    Lee, Kuan Yew (1923-2015).
    Współwytwórcy:
    Allison, Graham T. (1940- ). Opracowanie
    Blackwill, Robert D. Opracowanie
    Wyne, Ali (1987- ). Opracowanie
    Bińczak, Halina. Tłumaczenie
    Kurhaus Publishing. pbl
    Data publikacji:
    2013
    Wydawca:
    Warszawa : Kurhaus Publishing Kurhaus Media
    Tematy:
    Lee, Kuan Yew (1923-2015)
    Polityka międzynarodowa od 1945 r.
    Polityka
    Wywiad dziennikarski
    Dostawca treści:
    Bibliografia CBW
    Książka
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