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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:
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:
Fabrication Of Porous Ti By Thermal Decomposition And Sintering Of PMMA/TiH2 Powder Compact
Wytwarzanie porowatego tytanu przez rozkład termiczny i spiekanie wyprasek PMMA/TiH2
Autorzy:
Jeon, K. Ch.
Kim, Y. D.
Suk, M.-J.
Oh, S.-T.
Powiązania:
https://bibliotekanauki.pl/articles/352341.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
porous Ti
PMMA powders
thermal decomposition of TiH2
pore structure
porowaty tytan
PMMA
rozkład termiczny
struktura porów
Opis:
Porous Ti with controlled pore structure was fabricated by thermal decomposition and sintering process using TiH2 powders and Polymethylmethacrylates (PMMA) beads as pore forming agent. The beads sizes of 8 and 50 μm were used as a template for fabricating the porous Ti. The TiH2 powder compacts with 20 and 70 vol% PMMA were prepared by uniaxial pressing and sintered for 2 h at 1100°C. TGA analysis revealed that the PMMA and TiH2 were thermally decomposed at about 400°C forming pores and at about 600°C into metallic Ti phase. The porosity increased with increase in the amount of PMMA addition. Also, the microstructure observation showed that the pore size and shape were strongly dependent on the PMMA shapes.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1375-1377
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ship Collision Avoidance by Distributed Tabu Search
Autorzy:
Kim, D.
Hirayama, K.
Okimoto, M.
Powiązania:
https://bibliotekanauki.pl/articles/116919.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Morski w Gdyni. Wydział Nawigacyjny
Tematy:
Safety of Navigation
Collision Avoidance
Distributed Tabu Search Algorithm (DTSA)
Distributed Local Search Algorithm (DLSA)
Quasi-Local Minimum (QLM)
Tabu Search Algorithm
Local Search Algorithm
Distributed Tabu Search
Opis:
More than 90% of world trade is transported by sea. The size and speed of ships is rapidly increasing in order to boost economic efficiency. If ships collide, the damage and cost can be astronomical. It is very difficult for officers to ascertain routes that will avoid collisions, especially when multiple ships travel the same waters. There are several ways to prevent ship collisions, such as lookouts, radar, and VHF radio. More advanced methodologies, such as ship domain, fuzzy theory, and genetic algorithm, have been proposed. These methods work well in one-on-one situations, but are more difficult to apply in multiple-ship situations. Therefore, we proposed the Distributed Local Search Algorithm (DLSA) to avoid ship collisions as a precedent study. DLSA is a distributed algorithm in which multiple ships communicate with each other within a certain area. DLSA computes collision risk based on the information received from neighboring ships. However, DLSA suffers from Quasi-Local Minimum (QLM), which prevents a ship from changing course even when a collision risk arises. In our study, we developed the Distributed Tabu Search Algorithm (DTSA). DTSA uses a tabu list to escape from QLM that also exploits a modified cost function and enlarged domain of next-intended courses to increase its efficiency. We conducted experiments to compare the performance of DLSA and DTSA. The results showed that DTSA outperformed DLSA.
Źródło:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation; 2015, 9, 1; 23-29
2083-6473
2083-6481
Pojawia się w:
TransNav : International Journal on Marine Navigation and Safety of Sea Transportation
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:
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:
Surface Treatment And Modification Of Graphene Using Organosilane And Its Thermal Stability
Obróbka powierzchniowa i modyfikacja grafenu przy użyciu organosilanu i jego stabilność termiczna
Autorzy:
Kim, D.-S.
Dhand, V.
Rhee, K.-Y.
Park, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/354056.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
graphite
thermal properties
Raman spectroscopy
surface treatment
3-APTES
grafit
właściwości termiczne
spektroskopia Ramana
obróbka powierzchniowa
Opis:
In this study, graphene was functionalized via acid oxidation in the presence of a mixture of concentrated sulfuric acid and nitric acid. The oxidized graphene was silanized using the coupling agent, 3-aminopropyltriethoxsilane, resulting in functionalized graphene. The oxidized graphene and functionalized graphene were characterized by X-Ray diffraction, Fourier transform infrared spectroscopy, High-resolution micro Raman spectroscopy, thermogravimetric analysis, and atomic force microscopy to confirm the presence of functional moieties on the graphene surface. Thermal studies also demonstrate that the functionalized material is thermally stable up to higher temperatures.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1387-1391
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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:
Distribution and Management of the Invasive Exotic Species Ambrosia Trifida and Sicyos Angulatus in the Seoul Metropolitan Area
Autorzy:
Kim, K. D.
Powiązania:
https://bibliotekanauki.pl/articles/124560.pdf
Data publikacji:
2017
Wydawca:
Polskie Towarzystwo Inżynierii Ekologicznej
Tematy:
Ambrosia trifida
exotic
invasive
management
Sicyos angulatus
spreading
urban ecosystem
Opis:
We investigated the status of invasive exotic plants disturbing the ecosystem of the Seoul metropolitan area and examined the management of such plants. We selected our study sites based on those used in previous studies and on information in databases. All flora were classified into 57 families and 211 species; we evaluated 253 plant communities. The representative, invasive exotic species were Sicyos angulatus, Lactuca scariola, Ambrosia trifida, Ambrosia artemisiifolia, and Eupatorium rugosum. Stands of A. trifida ranged in area from 214 to 16,882 m2 and were present in riparian zones, road and forest edges, slopes, and other open habitats at all sites, covering an average of 37.87% of all study areas. In Gwangju, Ansan, and Anyang cities and in Yeoncheon-gun, A. trifida coverage was >50%; the total mean coverage was near-continuous along the Han and the South Han rivers, broken only by cliffs in some riparian zones, and anthropogenic constructions. A. trifida and S. angulatus require careful management because of extensive growth, shading, and twining. The biodiversity of native species may be conserved by physical eradication of these plants. We describe the extents and distribution patterns of these two representative invasive exotic species in the enormous urban ecosystem of Seoul.
Źródło:
Journal of Ecological Engineering; 2017, 18, 5; 27-36
2299-8993
Pojawia się w:
Journal of Ecological Engineering
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:
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:
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:
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:
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:
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

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