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    Wyświetlanie 1-41 z 41
    Tytuł:
    Hardness and Microstructure of Mixed Al-CNF Powder Extrusion
    Autorzy:
    Kim, D.-H.
    Kim, T.-J.
    Lim, S.-G.
    Powiązania:
    https://bibliotekanauki.pl/articles/351170.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Al-CNF composite
    cold isotatic
    presses
    powder extrusion
    LED
    microstructure
    Opis:
    In this study, mechanical properties and microstructures of extruded aluminum matrix composites were investigated. The composite materials were manufactured by two step methods: powder metallurgy (mixture of aluminum powder and carbon fiber using a turbular mixer, pressing of mixed aluminum powder and carbon fiber using a cold isostatic pressing) and hot extrusion of pressed aluminum powder and carbon fiber. For the mixing of Al powder and carbon fibers, aluminum powder was used as a powder with an average particle size of 30 micrometer and the addition of the carbon fibers was 50% of volume. In order to make mixing easier, it was mixed under an optimal condition of turbular mixer with a rotational speed of 60 rpm and time of 1800s. The process of the hot-extrusion was heated at 450°C for 1 hour. Then, it was hot-extruded with a condition of extrusion ratio of 19 and ram speed of 2 mm/s. The microstructural analysis of extruded aluminum matrix composites bars and semi-solid casted alloys were carried out with the optical microscope, scanning electron microscope and X-ray diffraction. Its mechanical properties were evaluated by Vickers hardness and tensile test.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1267-1270
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Temperature Effect on the Growth Rate and Physical Characteristics of SnO2 Thin Films Grown by Atomic Layer Deposition
    Autorzy:
    Kim, D.
    Kim, D. H.
    Riu, D.-H.
    Choi, B. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/353808.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    atomic layer deposition
    tin oxide
    growth rate
    film density
    optical band gap
    Opis:
    Among the various thin film coating techniques, atomic layer deposition (ALD) has features of good controllability of the thickness, excellent step-coverage in 3-dimensional object even in the sub-nm thickness range at the relatively low deposition temperature. In this study, SnO2 thin films were grown by ALD in the variation of substrate temperatures from 150 to 250°C. Even such a low temperature may influence on the growth kinetics of the ALD reaction and thus the physical characteristics of thin films, such as crystallinity, film density and optical band gap, etc. We observed the decrease of the growth rate with increasing substrate temperature, at the same time, the density of the film was decreased with increasing temperature. Steric hindrance effect of the precursor molecule was attributed to the inverse relationship of the growth temperature and growth rate as well as the film density. Optical indirect band gap energy (~3.6 eV) of the ALD-grown amorphous SnO2 films grown at 150°C was similar with that of the literature value, while slightly lower band gap energy (~3.4 eV) was acquired at the films grown at higher temperature.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 2; 1061-1064
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Error reduction of the Doppler lidar signal using a re-normalization method
    Autorzy:
    Park, N G
    Baik, S H
    Park, S K
    Kim, D L
    Kim, D. H.
    Powiązania:
    https://bibliotekanauki.pl/articles/173914.pdf
    Data publikacji:
    2014
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    injection-seeded laser
    Doppler lidar
    frequency locking
    wind lidar
    Doppler velocity measurement
    Opis:
    In this paper, we present a re-normalization method for a Doppler signal of a Doppler lidar system. For the Doppler lidar system, we used an injection-seeded pulsed Nd:YAG laser as a transmitter and an iodine cell as a Doppler frequency discriminator. A frequency locking system that uses the absorption feature of iodine gas is too sensitive to the external or internal noises (iodine cell temperature instability, laser frequency fluctuation, environmental noises, etc.) to maintain its locking point ideally, and this frequency locking error makes the Doppler lidar system acquire the noises as the Doppler frequency shifts. To reduce the Doppler signal error induced by a frequency locking error, we used a re-normalization method by an addition of a laser beam path separated from a transmitter to the Doppler frequency discriminator for re-normalization. In this method, fluctuations of the Doppler signal were reduced using the reference signal. The reduced amount of standard deviation between the Doppler signal and the re-normalization signal was 4.838×10–3 and the Doppler signals showed a 53.3% fluctuation reduction of the averaged error value by this method.
    Źródło:
    Optica Applicata; 2014, 44, 1; 103-111
    0078-5466
    1899-7015
    Pojawia się w:
    Optica Applicata
    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:
    A Study on Discharge Characteristics by Using MF and RF Power in Remote Dielectric Barrier Discharge
    Autorzy:
    Kim, D.
    Shim, Y.
    Kim, H.
    Han, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1398758.pdf
    Data publikacji:
    2016-04
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    52.77.Bn
    Opis:
    We have developed an atmospheric pressure plasma apparatus of remote dielectric barrier discharge (RDBD) applicable for a large area. We have systematically studied the characteristics of medium frequency (MF, 40 kHz) and radio frequency (RF, 13.56 MHz) discharge using an optical emission spectroscope. Nitrogen (N₂) and argon (Ar) gases were used in the MF and RF discharge excitation, respectively, in a mixture with clean dry air (CDA). The peak of oxygen radical (O*₂) appears at 259.3 nm when the RDBD is employed. Furthermore, intensive peaks are observed at gas ratios of N₂:CDA=100:1 in MF excitation and at gas ratios of Ar:CDA=70:0.5 in RF discharge excitation. On the other hand, the contact angle shows about 5° in PET samples after the RDBD treatment using the RF and MF discharge excitation. Surface analyses of polyethylene terephthalate (PET) samples were carried out using an atomic force microscope and X-ray photoelectron spectroscope.
    Źródło:
    Acta Physica Polonica A; 2016, 129, 4; 707-710
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect of natural organic matter on adsorption of ionic and non-ionic pharmaceuticals to granular activated carbon
    Autorzy:
    Oh, H.
    Urase, T.
    Simazaki, D.
    Kim, H.
    Powiązania:
    https://bibliotekanauki.pl/articles/208222.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
    Tematy:
    adsorpcja
    grupa karboksylowa
    kwas klofibrowy
    granulowany węgiel aktywny
    węgiel aktywny
    naturalne substancje organiczne
    farmaceutyki
    adsorption
    carboxylic group
    clofibric acid
    granular activated carbons
    natural organic matters
    pharmaceuticals
    Opis:
    Adsorption of clofibric acid (CA) and propyphenazone (PPZ) to virgin granular activated carbon (GAC) and preloaded GAC was evaluated in the absence or presence of natural organic matter (NOM). In spite of lower log K ow, PPZ showed higher selectivity to GAC than CA, which has a carboxylic group. Adsorption competition between CA and PPZ in binary solutes system decreased the amount of individual compound adsorbed to GAC. Adsorption isotherm data obtained in the presence of NOM showed that NOM in bulk solution or preloaded on GAC could significantly reduce the amounts of CA and PPZ adsorbed to GAC.
    Źródło:
    Environment Protection Engineering; 2013, 39, 4; 15-28
    0324-8828
    Pojawia się w:
    Environment Protection Engineering
    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:
    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:
    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:
    Preparation of Nickel Powders by Reduction of Nickel Hydroxide Using the Taylor Fluid Flow
    Autorzy:
    Park, I.-J.
    Kim, D.-W.
    Kim, G.-H.
    Chae, H.-J.
    Jung, H.-C.
    Powiązania:
    https://bibliotekanauki.pl/articles/355021.pdf
    Data publikacji:
    2018
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    Ni(OH)2
    nickel
    Taylor fluid flow
    fine powder
    Opis:
    In this study, Ni(OH)2 was synthesized by the continuous reaction by the Taylor fluid flow and compared with those prepared from the conventional batch type reaction. The nickel powders were synthesized by reduction of Ni(OH)2 in an aqueous solution with hydrazine hydrate acting as the reductant. And then the characteristics of the nickel powder according to the synthesis method were compared. The average particle size of the synthesized Ni(OH)2 using Taylor reactor was generally decreased about 1.5~2.5 times more than the batch reaction. The nickel powders prepared by the batch reaction highly agglomerated with non-uniform particles. In the Taylor reaction, the agglomeration of particles was broken and uniform nickel powder was produced.
    Źródło:
    Archives of Metallurgy and Materials; 2018, 63, 3; 1443-1447
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effect Of Carbon Nanotubes On The Properties Of Spark Plasma Sintered ZrO2/CNT Composites
    Wpływ nanorurek węglowych na właściwości spiekanych metodą sps kompozytów ZrO2/CNT
    Autorzy:
    Shim, D. H.
    Jung, S. S.
    Kim, H. S.
    Cho, H.
    Kim, J. K.
    Kim, T. G.
    Yoon, S. J.
    Powiązania:
    https://bibliotekanauki.pl/articles/351266.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    CNT
    ZrO2
    composite
    SPS
    kompozyty
    Opis:
    Zirconia matrix ZrO2/CNT composite materials reinforced with multiwall carbon nanotubes were fabricated using a spark plasma sintering technique. The effects of the amount of CNTs addition, sintering temperature and sintering pressure on the properties of the resulting ZrO2/CNT composites were examined. 0 to 9 vol. % CNTs were dispersed in zirconia powder, and the resulting mixture was sintered. The electrical conductivity, hardness, flexural strength, and density were measured to characterize the composites. The friction and wear properties of the composites were also tested. The flexural strength and friction coefficient of the composites were improved with up to 6 vol.% of CNT addition and the flexural strength showed a close relationship with the relative density of the composite. The electrical conductivity increased with increasing proportion of the CNTs, but the efficiency was reduced at more than 6 vol.% CNTs.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1315-1318
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Similarity of chromosome structure among Populus tremula var. davidiana, Populus alba and their hybrids revealed by FISH karyotype analysis
    Autorzy:
    Kim, Y.G.
    Kwon, S.H.
    Kang, H.I.
    Yoem, D.B.
    Kim, K.W.
    Kim, H.H.
    Kang, K.S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2077655.pdf
    Data publikacji:
    2020
    Wydawca:
    Polska Akademia Nauk. Instytut Dendrologii PAN
    Tematy:
    Karyotype analysis
    Fluorescence in situ hybridization
    Ribosomal DNA site
    Poplar
    Cytogenetics
    Opis:
    The genus Populus is one of the important tree species in Korean peninsula and many other coun- tries in the world. It represents the model species of forest genomics because it grows fast and reproduces rapidly. In this reason, their genetic characteristics have been well studied and the whole genome has been sequenced completely in some species. However, cytogenetic study of the genus Populus has been limited. In the present study, karyotypes of Korean aspen (P. tremula var. davidiana), Silver poplar (P. alba) and their two hybrids, Suwon aspen (P. tremula var. glandulosa) and Hyun aspen (P. alba × P. tremula var. glandulsa) were analyzed by means of the fluorescence in situ hybridization (FISH). Root samples were collected from mature trees in the demonstration forest, located at Suwon, Kyonggi province in South Korea. The fresh root cells were examined by DAPI (4’,6-diamidino-2-phenylindole) staining and FISH using 45S rDNA and 5S rDNA probes. As the results, the chromosome compositions of all species were the same as 2n = 38. The karyotype formulas of Korean aspen, Silver poplar, Suwon aspen and Hyun aspen were 28m + 6sm + 4st (2sat), 26m + 10sm (2sat) + 2st, 26m + 12sm (2sat) and 28m + 10sm (2sat), respectively. The four species had one pair of 45S rDNA site and one pair of 5S rDNA site in common with FISH karyotypes. The similarity of FISH karyotypes among four species indicated close genetic relationship and coexistence of their interspecific hybrids. This research will provide genetic information on cytogenetic research of Populus and genetic mapping that can be applied to the breeding program of Populus in the near future.
    Źródło:
    Dendrobiology; 2020, 83; 68-74
    1641-1307
    Pojawia się w:
    Dendrobiology
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Aluminum Nitride Formation From Aluminum Oxide/Phenol Resin Solid-Gel Mixture By Carbothermal Reduction Nitridation Method
    Wytwarzanie azotku aluminium z żelowej mieszaniny tlenku aluminium z żywicą fenolową metodą azotowania podczas carbotermicznej redukcji
    Autorzy:
    Mylinh, D. T.
    Yoon, D. H.
    Kim, C.-Y.
    Powiązania:
    https://bibliotekanauki.pl/articles/356779.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    aluminum nitride
    powder
    carbothermal reduction
    nitridation
    solid-gel mixture
    azotek aluminium
    proszek
    redukcja karbotermiczna
    azotowanie
    żelowa mieszanina
    Opis:
    Hexagonal and cubic crystalline aluminum nitride (AlN) particles were successfully synthesized using phenol resin and alpha aluminum oxide (α-Al2O3) as precursors through new solid-gel mixture and carbothermal reduction nitridaton (CRN) process with molar ratio of C/Al2O3 = 3. The effect of reaction temperature on the decomposition of phenol resin and synthesis of hexagonal and cubic AlN were investigated and the reaction mechanism was also discussed. The results showed that α-Al2O3 powder in homogeneous solid-gel precursor was easily nitrided to yield AlN powder during the carbothermal reduction nitridation process. The reaction temperature needed for a complete conversion for the precursor was about 1700°C, which much lower than that when using α-Al2O3 and carbon black as starting materials. To our knowledge, phenol resin is the first time to be used for synthesizing AlN powder via carbothermal reduction and nitridation method, which would be an efficient, economical, cheap assistant reagent for large scale synthesis of AlN powder.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1551-1555
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    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:
    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:
    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:
    Molecule dissociation at the Fe3O4 (001) surface
    Autorzy:
    Kim-Ngan, N.-T. H.
    Jagło, D.
    Sitko, D.
    Soszka, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/411955.pdf
    Data publikacji:
    2013
    Wydawca:
    Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
    Tematy:
    Magnetite surface
    low energy ion scattering
    molecule dissociation
    Opis:
    The molecular dissociation at the single-crystalline Fe3O4 (001) surface has been investigated using the diatomic H+2 , D+2 and N+2 molecules in the energy range of 3�{8 keV and in the temperature range of 90 K�{300 K. The single collision of ions released from dissociation with the surface atoms was observed only for the N2+ molecules. The detail analysis confirmed that for the light molecules such as H2+ and D2+ the charge-transfer process dominate the interaction of a molecule with the magnetite surface. A large change in the scattered ion yields around the Verwey phase transition temperature was observed indicating a strong correlation between the molecule dissociation and the electronic state of the magnetite surface.
    Źródło:
    International Letters of Chemistry, Physics and Astronomy; 2013, 2; 1-10
    2299-3843
    Pojawia się w:
    International Letters of Chemistry, Physics and Astronomy
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of InAs Coverage on Transition of Size Distribution and Optical Properties of InAs Quantum Dots
    Autorzy:
    Kim, G.
    Jeon, S.
    Cho, M.
    Choi, H.
    Kim, D.
    Kim, M.
    Kwon, Y.
    Choe, J.
    Kim, J.
    Leem, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/1535820.pdf
    Data publikacji:
    2010-10
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    81.15.Hi
    68.37.Ps
    78.55.Cr
    78.67.Hc
    Opis:
    The influence of InAs coverage on the formation of self-assembled quantum dots grown by molecular-beam epitaxy was investigated by atomic force microscopy and photoluminescence measurements. As the InAs coverage increased from 2.0 to 3.0 monolayers, the quantum dot density decreased from 1.1 × $10^{11}$ to 1.36 × $10^{10} cm^{-2}$. This result could be attributed to the coalescence of neighboring small InAs quantum dots resulting in the formation of much larger InAs quantum dots with lower quantum dot density. Atomic force microscopy results revealed that as the InAs quantum dot coverage increased, the transition of size distribution of InAs quantum dots from single-modal to multimodal occurred. The temperature-dependent photoluminescence spectra showed that the photoluminescence spectra red shifted and the photoluminescence peak intensity decreased as the InAs coverage increased. The thermal activation energy was strongly dependent on the InAs coverage, and for InAs quantum dots with 3.0 ML thick InAs coverage, this energy was estimated to be 147 meV.
    Źródło:
    Acta Physica Polonica A; 2010, 118, 4; 673-676
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    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:
    Isotopic water separation using AGMD and VEMD
    Autorzy:
    Kim, J.
    Park, S.
    Kim, T.-S.
    Jeong, D.-Y.
    Ko, K.-H.
    Powiązania:
    https://bibliotekanauki.pl/articles/147314.pdf
    Data publikacji:
    2004
    Wydawca:
    Instytut Chemii i Techniki Jądrowej
    Tematy:
    AGMD
    VEMD
    oxygen isotopes
    PET
    FDG
    Opis:
    The 18O isotopic water permeation and separation characteristics of a hydrophobic PTFE membrane using Air Gap Membrane Distillation (AGMD) and Vacuum Enhanced Membrane Distillation (VEMD) were investigated. Permeation fluxes were measured by weighing the collected membrane-permeated water vapor. 18O/16O of each water sample was analyzed by the Tunable Diode Laser Absorption Spectroscopy (TDLAS). We observed the effects of the air filled membrane pores and the temperature gradient applied to the membrane surfaces on the vapor permeation flux and the oxygen isotope separation for the first time. For both AGMD and VEMD, the permeation flux and the degree of 18O separation increased as the membrane interfacial temperature gradient increased. Even though, oxygen isotope separation and the permeation flux for VEMD is slightly higher than AGMD, the latter may be more efficient from the system's operational point of view.
    Źródło:
    Nukleonika; 2004, 49, 4; 137-142
    0029-5922
    1508-5791
    Pojawia się w:
    Nukleonika
    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:
    Solvent Extraction of Co, Ni and Mn from NCM Sulfate Leaching Solution of Li(NCM)O2 Secondary Battery Scraps
    Autorzy:
    Hong, H. S.
    Kim, D. W.
    Choi, H. L.
    Ryu, S.-S.
    Powiązania:
    https://bibliotekanauki.pl/articles/355577.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    waste recycling
    NCM-system lithium ion battery
    reduction
    leaching
    Opis:
    As a part of the study on recycling Li(NCM)O2 lithium-ion battery scraps, solvent extraction experiments were performed using different extraction agents such as PC88A, Cyanex272 and D2EHPA to separate Co, Ni and Mn from the leaching solution. When the ratio of Mn to Ni was about 0.4 in the leaching solution, the separation factor for Co and Mn was found to be less than 10 so that the separation of Co and Ni was insufficient. When solvent extraction was done using the solution with the lower Mn/Ni ratio of 0.05 where Mn was removed by potassium permanganate and chlorine dioxide, more than 99% of Mn could be extracted through five courses of extraction using 30vol% D2EHPA while the extraction rates of Co and Ni were around 17% and 11%, respectively. In the case that Mn was removed from the solution, the extraction rate of Co was higher than 99% whereas less than 7% Ni was extracted using Cyanex272 suggesting that Co and Ni elements were effectively separated.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1011-1014
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Effects of Grain Boundary Morphologies on Stress Corrosion Cracking of Alloy 600
    Autorzy:
    Kim, H. P.
    Choi, M. J.
    Kim, S. W.
    Kim, D. J.
    Lim, Y. S.
    Hwang, S. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/352569.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    alloy 600
    NaOH
    stress corrosion cracking
    grain boundary morphologies
    Opis:
    Effects of grain boundary morphologies on stress corrosion cracking (SCC) of Alloy 600 have been studied in 40% NaOH at 315°C using C-ring specimens. The configuration of the grain boundary and the intergranular carbide density were controlled by heat treatment. SCC tests were performed at +150 mV above the corrosion potential. The specimen with a serrated grain boundary showed higher SCC resistance than that with a straight grain boundary. This appears to be caused by the fact that the specimen with the serrated grain boundary has longer SCC path. SCC resistance also increased with intergranular carbide density probably due to enhanced relaxation of stress at intergranular carbide.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1415-1419
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    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:
    Achene morphology and pericarp anatomy of Anemone, Hepatica, and Pulsatilla (Anemoninae, Ranunculaceae)
    Autorzy:
    Ghimire, B.
    Yum, D.
    Kim, J.H.
    Jeong, M.J.
    Powiązania:
    https://bibliotekanauki.pl/articles/2117680.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Czasopisma i Monografie PAN
    Tematy:
    achene
    Anemoninae
    pericarp
    Ranunculaceae
    taxonomy
    Opis:
    The achene morphology and pericarp anatomy of 12 taxa representing three genera (Anemone, Hepatica, and Pulsatilla) of the subtribe Anemoninae were investigated using microtome and light microscopy to evaluate the taxonomic implications of achene characters. The achenes of Anemone were elliptical or obovoid and beaked, whereas the achene of Hepatica and Pulsatilla were obovoid and elliptical, respectively. Noticeable variations in both quantitative and qualitative features of achenes were observed among the species of the three genera. One-way analysis of variance indicated that the quantitative achene variables among the species were highly significant (P<0.001). Pearson’s correlation coefficient also showed a significant correlation between different achene variables. The pericarp structure, particularly the number of cell layers and cell forms in the exocarp and endocarp, seems to be very useful for species delimitation in Anemone and Hepatica. The nature of the endotesta could provide substantial proof for sub-generic classification in Anemone. Unweighted paired group analysis showed the utility of achene features for taxonomic groupings of the species within the studied genera. Although the specimen samples represented a limited range of taxa, the achene features and pericarp anatomy provided a reasonable source for the taxonomic treatment of the studied genera within the subtribe.
    Źródło:
    Acta Biologica Cracoviensia. Series Botanica; 2021, 63, 1; 7-19
    0001-5296
    Pojawia się w:
    Acta Biologica Cracoviensia. Series Botanica
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Morphology of strobili at different development positions and cone and seed characteristics of Pinus densiflora f. multicaulis
    Autorzy:
    Kwon, S.H.
    Kim, Y.G.
    Kang, H.I.
    Shim, D.
    Kang, K.S.
    Powiązania:
    https://bibliotekanauki.pl/articles/2078259.pdf
    Data publikacji:
    2021
    Wydawca:
    Polska Akademia Nauk. Instytut Dendrologii PAN
    Tematy:
    bisexual strobili
    sex reversal
    microsporangia
    megasporangia
    cone analysis
    Opis:
    Pinus densiflora f. multicaulis is a rare and unusual form of genus Pinus. It has excellent ornamen- tal values due to many trunks from its root collar, and produces female, male, and bisexual strobili on the same tree. However, there is limited study whether the bisexual strobili are functional, mature lateral cones produce filled seeds, and the seeds from the mature lateral cones germinate and grow as well as those from mature apical cones. The structure of apical female, and lateral male and bisexual strobili were analyzed in an open-pollination-progeny population. The strobili were photographed to obtain external, cross-section, and radial-section images using a 45× stereoscopic microscope. Radial sections of strobili were imaged using scanning electron microscopy. Characteristics of apical and lateral cones and seeds were surveyed by cone analysis and germination test. P. densiflora f. multicaulis developed typical female strobili apically, and ordinary male and bisexual strobili laterally. Additionally, female strobili developed laterally whereas the male strobili were normally located. The mature lateral female strobili had the same structure as the apical female. In the mature bisexual strobili, the proportion of male and female tissue was unequal. The cones developed from lateral female strobili showed highly significant differences in the length, width, and weight, being shorter (32.7%), narrower (26.9%), and lighter (59.8%) than those from apical female strobili. Both types produced filled seeds and seedlings, and well significant positive correlations were found among characteristics of seeds from apical and lateral female strobili. The initial seed germination rate of the seeds from apical female strobili was higher than that of seeds from lateral female strobili, but the difference decreased over time. The viability and spatial distribution of the female and male tissue of bisporangiate cones, and their frequent occurrence suggests a common mechanism for the production of bisporangiate structures in seed plants.
    Źródło:
    Dendrobiology; 2021, 85; 51-59
    1641-1307
    Pojawia się w:
    Dendrobiology
    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:
    Surface Investigations of Selected Materials by Low-Energy Ion Scattering Technique
    Autorzy:
    Goc-Jagło, D.
    Sitko, D.
    Jagło, G.
    Kim-Ngan, N.-T. H.
    Soszka, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/2047339.pdf
    Data publikacji:
    2007-05
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    68.35.Rh
    71.20.Be
    71.20.Eh
    77.80.Bh
    Opis:
    Surfaces of three selected materials were investigated by means of low-energy ion-scattering technique: (1) the magnetite (Fe$\text{}_{3}$O$\text{}_{4}$) exhibiting the so-called Verwey transition (T$\text{}_{V}$(bulk)=125 K) accompanied by a small cubic-monoclinic crystal distortion, (2) the intermetallic compound NdMn$\text{}_{2}$ undergoing an antiferromagnetic-paramagnetic phase transition (T$\text{}_{N}$=104 K) accompanied by a large crystal distortion with a volume change of 1%, and (3) the typical insulator BaTiO$\text{}_{3}$ with two structural transitions below 300 K. The primary energy of the (Ne$\text{}^{+}$, Ar$\text{}^{+}$) ion beam was in the range of 4-8 keV, and the low-energy ion-scattering spectra were collected in the temperature range of 85-300 K. A large influence from the Verwey transition on the neutralization and re-ionization of scattered ions from magnetite surface was observed, while no visible change at the magnetic phase transition in NdMn$\text{}_{2}$ was revealed in the low-energy ion-scattering spectra. A strong dependence of the characteristics of the low-energy ion-scattering spectra on the irradiated time was observed for BaTiO$\text{}_{3}$ indicating that this surface was heavily charged by ion bombardments.
    Źródło:
    Acta Physica Polonica A; 2007, 111, 5; 763-771
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    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:
    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:
    Growth of NdBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ Superconducting Thin Films on SrTiO$\text{}_{3}$(100) and LaSrGaO$\text{}_{4}$(100) Substrates
    Autorzy:
    Park, J.-C.
    Ha, D. H.
    Kim, I.-S.
    Park, Y.K.
    Powiązania:
    https://bibliotekanauki.pl/articles/1964239.pdf
    Data publikacji:
    1997-07
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    74.76.Bz
    Opis:
    NdBa$\text{}_{2}$Cu$\text{}_{3}$O$\text{}_{7-δ}$ superconducting thin films were grown on SrTiO$\text{}_{3}$(100) and LaSrGaO$\text{}_{4}$(100) substrates by off-axis rf sputtering and pulsed laser deposition. The effects of several deposition parameters, e.g. gas pressure, substrate temperature and energy density were studied. Thin films grown by off-axis rf sputtering were highly c-axis oriented, but those by pulsed laser deposition were predominantly a-axis oriented under our deposition conditions. However, the c-axis oriented portion for the films grown by pulsed laser deposition was increased by increasing the temperature above 800°C. T$\text{}_{c(zero)}$ was 87 K and 83 K for the c- and a-axis oriented films respectively. The critical current density of c-axis oriented films was 10$\text{}^{6}$-10$\text{}^{7}$ A/cm$\text{}^{2}$ below 60 K.
    Źródło:
    Acta Physica Polonica A; 1997, 92, 1; 105-114
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Understanding the Oxide Dispersion Behavior of Yttria in Metal Matrix of MA956 Alloy through High-Energy Milling and Hot Press Sintering
    Autorzy:
    Swain, B.
    Han, D.
    Kim, G.-H.
    Kong, M.-S.
    Ahn, B.
    Powiązania:
    https://bibliotekanauki.pl/articles/351770.pdf
    Data publikacji:
    2017
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    ODS
    mechanical alloying
    high-energy milling
    oxide particle distribution
    Opis:
    MA956 (Fe-Cr-Al) alloy powder was high-energy ball milled with various amount of yttria contents (1,2,3, and 4 wt.%) to fabricate an oxide dispersion strengthened alloy. The milled powders were then consolidated using hot press sintering at 1150°C. The surface morphology and crystal structure of MA956 powder during the high-energy milling depending on the yttria contents was investigated using particle size analysis, X-ray diffraction, and scanning electron microscopy. The microstructural analysis of sintered alloy was performed using transmission electron microscopy and energy dispersive spectroscopy to evaluate the dispersion behavior of yttrium oxide. The results showed that, as yttria contents increased, the oxide particles became finer and are uniformly distributed during the high-energy milling. However, after the sintering, the oxide particles were coarsened with more than 3 wt.% of yttria addition.
    Źródło:
    Archives of Metallurgy and Materials; 2017, 62, 2B; 1377-1381
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    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:
    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:
    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:
    Second Harmonic Generation, Beam Dynamics and Spatial Soliton Generation in Periodically Poled KTiOPO$\text{}_{4}$
    Autorzy:
    Kim, H.
    Jankovic, L.
    Stegeman, G.
    Carrasco, S.
    Torner, L.
    Katz, M.
    Eger, D.
    Powiązania:
    https://bibliotekanauki.pl/articles/2035660.pdf
    Data publikacji:
    2003
    Wydawca:
    Polska Akademia Nauk. Instytut Fizyki PAN
    Tematy:
    42.65.Jx
    42.65.Ky
    42.65.Tg
    Opis:
    Spatial solitons were investigated in periodically poled KTiOPO$\text{}_{4}$ under conditions of second harmonic generation and many new features associated with soliton generation in quasi-phase-matched samples were observed. The effects on the second harmonic generation tuning curves of the beam narrowing mechanisms responsible for soliton generation were found to be dramatic. It was demonstrated experimentally that the mutual collapse of the fundamental and harmonic beams is a complex phenomenon.
    Źródło:
    Acta Physica Polonica A; 2003, 103, 2-3; 107-119
    0587-4246
    1898-794X
    Pojawia się w:
    Acta Physica Polonica A
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Recovery Of Electrodic Powder From Spent Nickel-Metal Hydride Batteries (NiMH)
    Odzyskiwanie proszku elektrodowego ze zużytych akumulatorów niklowo-wodorkowych (NiMH)
    Autorzy:
    Shin, S. M.
    Shin, D. J.
    Jung, G. J.
    Kim, Y. H.
    Wang, J. P.
    Powiązania:
    https://bibliotekanauki.pl/articles/356110.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    nickel-metal hybride (NiMH)
    electrodic powder
    nickel
    rare earth elements (REE)
    thermal treatment
    akumulator niklowo-wodorkowy
    proszek elektrodowy
    nikiel
    pierwiastki ziem rzadkich
    obróbka termiczna
    Opis:
    This study was focused on recycling process newly proposed to recover electrodic powder enriched in nickel (Ni) and rare earth elements (La and Ce) from spent nickel-metal hydride batteries (NiMH). In addition, this new process was designed to prevent explosion of batteries during thermal treatment under inert atmosphere. Spent nickel metal hydride batteries were heated over 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) and energy dispersive X-ray spectroscopy (EDX) and image of the powder was taken by scanning electron microscopy (SEM). It was finally found that nickel and rare earth elements were mainly recovered to about 45 wt.% and 12 wt.% in electrodic powder, respectively.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1139-1143
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Synthesis And Electrochemical Characteristics Of Mechanically Alloyed Anode Materials SnS2 For Li/SnS2 Cells
    Synteza mechaniczna i charakterystyka elektrochemiczna materiałów anodowych SnS2 dla ogniw Li/SnS2
    Autorzy:
    Hong, J. H.
    Liu, X. J.
    Park, D. K.
    Kim, K. W.
    Ahn, H. J.
    Ahn, I. S.
    Powiązania:
    https://bibliotekanauki.pl/articles/356903.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    MA
    Li/SnS2 cell
    PCA
    wet milling process and electrochemical characteristics
    ogniwa Li/SnS2
    charakterystyka elektromechaniczna
    Opis:
    With the increasing demand for efficient and economic energy storage, tin disulfide (SnS2), as one of the most attractive anode candidates for the next generation high-energy rechargeable Li-ion battery, have been paid more and more attention because of its high theoretical energy density and cost effectiveness. In this study, a new, simple and effective process, mechanical alloying (MA), has been developed for preparing fine anode material tin disulfides, in which ammonium chloride (AC), referred to as process control agents (PCAs), were used to prevent excessive cold-welding and accelerate the synthesis rates to some extent. Meanwhile, in order to decrease the mean size of SnS2 powder particles and improve the contact areas between the active materials, wet milling process was also conducted with normal hexane (NH) as a solvent PCA. The prepared powders were both characterized by X-ray diffraction, Field emission-scanning electron microscopeand particle size analyzer. Finally, electrochemical measurements for Li/SnS2 cells were takenat room temperature, using a two-electrode cell assembled in an argon-filled glove box and the electrolyte of 1M LiPF6 in a mixture of ethylene carbonate(EC)/dimethylcarbonate (DMC)/ethylene methyl carbonate (EMC) (volume ratio of 1:1:1).
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1191-1194
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    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 Metal Carbide Composite Diffusion Bonding For Mechanical Seal
    Badanie łączenia dyfuzyjnego kompozytu metal węglik na mechaniczne uszczelnienie
    Autorzy:
    Kim, D.-K.
    Shon, I.-J.
    Song, J.
    Ryu, W.-J.
    Shin, H.-Ch.
    Kwon, E.-Y.
    Shin, H.
    Kang, S.-J.
    Powiązania:
    https://bibliotekanauki.pl/articles/356399.pdf
    Data publikacji:
    2015
    Wydawca:
    Polska Akademia Nauk. Czytelnia Czasopism PAN
    Tematy:
    diffusion bonding
    nanostructures
    mechanical seal
    hard metal
    mechanical properties
    łączenie
    nanostruktura
    uszczelnienie mechaniczne
    twardy metal
    właściwości mechaniczne
    Opis:
    Mechanical Seal use highly efficient alternative water having a great quantity of an aqueous solution and has an advantage no corrosion brine. Metal Carbide composites have been investigated as potential materials for high temperature structural applications and for application in the processing industry. The existing Mechanical seal material is a highly expensive carbide alloy, and it is difficult to take a price advantage. Therefore the study of replacing body area with inexpensive steel material excluding O-ring and contact area which demands high characteristics is needed. The development of WC-Ni base carbide alloy optimal bonding composition technique was accomplished in this study. To check out the influence of bonding temperature and time, bonding characteristics of sintering temperature was experimented. The bonding statuses of this test specimen were excellent. The hardness of specimen and bonding rate were measured using ultrasound equipment. In this work, Powder of WC (involved VC, Cr), Co and Mo2C mixed by attrition milling for 24hours. Nanostructured WC-27.6wt.%Ni-1.5wt.%Si-0.11wt.%VC-1.1wt.%B4C composite were fabricated at 1190°C by high temperature vacuum furnace. To check out the influence of bonding temperature and time, bonding characteristics of sintering temperature was experimented. Its relative density was about 99.7%. The mechanical properties (hardness and fracture toughness) were 87.2 HRA and 4.2 M·Pam1/2, respectively. The bonding status of this test specimen was excellent and the thickness of bonding layer was 20 ~30§ at 1050 and 1060°C bonding temperature.
    Źródło:
    Archives of Metallurgy and Materials; 2015, 60, 2B; 1479-1483
    1733-3490
    Pojawia się w:
    Archives of Metallurgy and Materials
    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
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