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Tytuł:
Graphite Nanosheet Exfoliation From Graphite Flakes Through Functionalization Using Phthalic Acid
Złuszczanie nanoarkuszy grafitu z płatków grafitu przy użyciu kwasu ftalowego
Autorzy:
Kim, J. H.
Lee, J. H.
Powiązania:
https://bibliotekanauki.pl/articles/351457.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
exfoliation
graphite nanosheet
functionalization
grafting molecule
Friedel-Crafts acylation
złuszczanie
nanoarkusz grafitu
funkcjonalizacja
kwas ftalowy
acylowanie Friedela-Craftsa
Opis:
In order to fabricate graphite nanosheets from graphite flakes, edge-functionalized graphite nanosheets were prepared by a functionalization method using phthalic acid as the molecule to be grafted. A polyphosphoric acid/P2O5 solution containing graphite and phthalic acid were heated at different temperatures for 72 h in a nitrogen atmosphere. It was confirmed by transmission electron microscopy and atomic force microscopy that the resultant phthalic acid-functionalized graphite nanosheets had a large surface area of 20.69 μm2 in average and an average thickness of 1.39 nm. It was also found by X-ray diffractometry and Fourier transform infrared spectroscopy (FT-IR) analysis that the functionalization caused the formation of C=O bonds at the edges of the graphite nanosheets. The yield from this functionalization method was found to be dependent on the reaction temperature, only when it is between 70 and 130°C, because of the dehydration of phthalic acid at higher temperatures. This was confirmed by FT-IR analysis and the observation of low thermal energies at low temperatures.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1251-1255
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Formation of Different Cu Nanopowders and Stability of Cu Fluids Produced by Electrical Explosion of Wire in Liquid
Autorzy:
Nguyen, M.-T.
Kim, J.-H.
Kim, J.-C.
Powiązania:
https://bibliotekanauki.pl/articles/355217.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Cu nanopowder
Cu nanofluids
electrical explosion of wire
stability of nanofluids
Opis:
In this study, copper nanoparticles and nanofluids were synthesized by electrical explosion of wire (EEW) in liquid media such as water, ethanol, and acetone. The effect of the different conditions on the properties of the as-synthesized Cu powders and nanofluids were investigated. X-ray diffraction (XRD) analysis was employed to measure the phase of the as-synthesized powder. Only pure Cu phase appeared in case of acetone condition, but CuO and CuO2 phases could be observed in the others. The EEWed particle size was broadened from under 50 to 100 nm. The results showed that acetone was the best condition for achieving smaller particles, preventing the oxidation of the Cu particles and good stability of the nanofluids.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1453-1457
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on detection of gross error in geodetic network adjustment
Autorzy:
Kim, J. H.
Kim, C. J.
Li, R. J.
Powiązania:
https://bibliotekanauki.pl/articles/145352.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sieć geodezyjna
sieć triangulacyjna
geodezja satelitarna
geodetic network adjustment
gross error
robust estimation
equivalent weight
Opis:
Generally, gross errors exist in observations, and they affect the accuracy of results. We review methods to detect the gross errors by Robust estimation method based on L1-estimation theory and their validity in adjustment of geodetic networks with different condition. In order to detect the gross errors, we transform the weight of accidental model into equivalent one using not standardized residual but residual of observation, and apply this method to adjustment computation of triangulation network, traverse network, satellite geodetic network and so on. In triangulation network, we use a method of transforming into equivalent weight by residual and detect gross error in parameter adjustment without and with condition. The result from proposed method is compared with the one from using standardized residual as equivalent weight. In traverse network, we decide the weight by Helmert variance component estimation, and then detect gross errors and compare by the same way with triangulation network In satellite geodetic network in which observations are correlated, we detect gross errors transforming into equivalent correlation matrix by residual and variance inflation factor and the result is also compared with the result from using standardized residual. The results of detection are shown that it is more convenient and effective to detect gross errors by residual in geodetic network adjustment of various forms than detection by standardized residual.
Źródło:
Geodesy and Cartography; 2018, 67, 1; 57-69
2080-6736
2300-2581
Pojawia się w:
Geodesy and Cartography
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:
Effect of Heat Treatment on the Microstructure and Tensile Deformation Behavior of Oxide Dispersion Strengthened Alloys Manufactured by Complex Milling Process
Autorzy:
Kim, Y.-K.
Kim, J.-H.
Gwon, J.-H.
Lee, K.-A.
Powiązania:
https://bibliotekanauki.pl/articles/352535.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ball milling
oxide dispersion strengthening
microstructure
tensile deformation behavior
Opis:
This study attempted to manufacture an ODS alloy by combining multiple milling processes in mechanical alloying stage to achieve high strength and fracture elongation. The complex milling process of this study conducted planetary ball milling, cryogenic ball milling and drum ball milling in sequential order, and then the microstructure and tensile deformation behavior were investigated after additional heat treatment. The oxide particles distributed within the microstructure were fine oxide particles of 5~20 nm and coarse oxide particles of 100~200 nm, and the oxide particles were confirmed to be composed of Cr, Ti, Y and O. Results of tensile tests at room temperature measured yield strength, tensile strength and elongation as 1320 MPa, 2245 MPa and 4.2%, respectively, before heat treatment, and 1161 MPa, 2020 MPa and 5.5% after heat treatment. This results indicate that the ODS alloy of this study gained very high strengths compared to other known ODS alloys, allowing greater plastic zones.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1335-1340
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of High-Strength Gray Cast Iron Using Permanent Magnet Scrap
Autorzy:
Park, S.-Y.
Kim, J. H.
Seo, S. J.
On, J. S.
Lim, K. M.
Powiązania:
https://bibliotekanauki.pl/articles/352204.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
gray cast iron
rare earth element
Nd-Fe-B magnet scrap
graphite formation
microstructure
Opis:
In this study, we have developed the manufacturing technology for high strength gray cast irons by using the spent permanent magnet scraps. The cast specimen inoculated by using a spent magnet scraps showed the excellent tensile strength up to 306MPa. This tensile strength value is 50MPa higher than that of the specimen cast without inoculation, and is similar to that of the specimen inoculated by using the expensive misch-metal. These superior mechanical properties are attributed to complex sulfides created during solidification that promote the formation and growth of Type-A graphite. It is therefore concluded that spent magnets scrap can provide an efficient and cost-effective inoculation agent for the fabrication of high-performance gray cast iron.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1113-1117
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study On The Electro-Refining Of Tin In Acid Solution From Electronic Waste
Badanie elektrorafinacji cyny w roztworze kwasu z e-odpadów
Autorzy:
Son, S. H.
Park, S. C.
Kim, J. H.
Kim, Y. H.
Lee, M. S.
Ahn, J.-W.
Powiązania:
https://bibliotekanauki.pl/articles/352665.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrorefining
tin
electronic waste
recycling
high purity
elektrorafinacja
cyna
odpady elektroniczne
recykling
Opis:
The tin metal could be retractable from wasted tin scrap, sludge, and wasted electroplated solution hydrometallurgical treatment, and purification process. In order to be used as resource of electronic devices, the retracted crude metal should be purified to the extent of higher than 99.9%. In this study, tin electro-refining process was performed to purify the casted tin crude metal at various experimental conditions: at the current density of 3, 5A/dm2, and in various electrolytes such as hydrochloric acid, sulfuric acid and methansulfonic acid. Additional experiment was conducted using Rotating Disk Electrode (RDE) in order to investigate the rate determining step of tin electro-refining process. The current efficiency, 65.6%, was achievable at the condition of current density, 5A/dm2, and in the electrolyte of Hydrochloric acid. During tin electro-refining process, impurity dissolved from tin crude metal into the electrolyte was analyzed using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), and the result showed the concentration of impurity metal gradually increased. Quantitative analysis on casted tin crude metal showed that it consists of tin with 93.9 wt.% and several impurity metals of Ag, Bi, Pb, Cu, and etc. After tin electro-refining process, the purity of tin increased up to 99.985 wt.%.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1217-1220
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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:
Extraction Factor Of Pure Ammonium Paratungstate From Tungsten Scraps
Współczynnik ekstrakcji czystego parawolframianu amonu z odpadów wolframowych
Autorzy:
Pee, J-H.
Kim, G. H.
Lee, H. Y.
Kim, Y. J.
Powiązania:
https://bibliotekanauki.pl/articles/356567.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
raw material
recycling
ammonium paratungstate
tungsten scraps
extraction
surowce
recykling
parawolfrawian amonu
odpady wolframowe
ekstrakcja
Opis:
Typical oxidation process of tungsten scraps was modified by the rotary kiln with oxygen burner to increase the oxidation rate of tungsten scraps. Also to accelerate the solubility of solid oxidized products, the hydrothermal reflux method was adapted. By heating tungsten scraps in rotary kiln with oxygen burner at around 900° for 2hrs, the scraps was oxidized completely. Then oxidized products (WO3 and CoWO4) was fully dissolved in the solution of NaOH by hydrothermal reflux method at 150° for 2hrs. The dissolution rate of oxidized products was increased with increasing the reaction temperature and concentration of NaOH. And then CaWO4 and H2WO4 could be generated from the aqueous sodium tungstate solution. Ammonium paratungstate (APT) also could be produced from tungstic acid using by aqueous ammonium solution. The morphologies (cubic and plate types) of APT was controlled by the stirring process of purified solution of ammonium paratungstate.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1403-1405
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extraction Factor Of Tungsten Sources From Tungsten Scraps By Zinc Decomposition Process
Współczynnik ekstrakcji związków wolframu z odpadów wolframowych w procesie rozkładu cynku
Autorzy:
Pee, J-H.
Kim, G. H.
Lee, H. Y.
Kim, Y. J.
Powiązania:
https://bibliotekanauki.pl/articles/354774.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
raw material
recycling
zinc decomposition process
tungsten carbide
tungstic acid
surowce
recykling
proces rozkładu cynku
węglik wolframu
kwas wolframowy
Opis:
Decomposition promoting factors and extraction process of tungsten carbide and tungstic acid powders in the zinc decomposition process of tungsten scraps which are composed mostly of tungsten carbide and cobalt were evaluated. Zinc volatility was suppressed by the enclosed graphite crucible and zinc volatilization pressure was produced in the reaction graphite crucible inside an electric furnace for ZDP (Zinc Decomposition Process). Decomposition reaction was done for 2hours at 650°, which 100% decomposed the tungsten scraps that were over 30 mm thick. Decomposed scraps were pulverized under 75μm and were composed of tungsten carbide and cobalt identified by the XRD (X-ray Diffraction). To produce the WC(Tungsten Carbide) powder directly from decomposed scraps, pulverized powders were reacted with hydrochloric acid to remove the cobalt binder. Also to produce the tungstic acid, pulverized powders were reacted with aqua regia to remove the cobalt binder and oxidize the tungsten carbide. Tungsten carbide and tungstic acid powders were identified by XRD and chemical composition analysis.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1311-1314
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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:
Sintering and Microstructures of SUS 316L Powder Produced by 3D Printing Process
Autorzy:
Kim, W. J.
Nguyen, H.-H.
Kim, H. Y.
Nguyen, M.-T.
Park, H. S.
Kim, J.-C.
Powiązania:
https://bibliotekanauki.pl/articles/356018.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stainless steel
3D printing
selective laser sintering
SUS 316L
flake powder
Opis:
Selective laser sintering (SLS) is a type of laminating sintering technique, using CO2 laser with (metal, polymer, and ceramic) powders. In this result, the flake SUS 316L was used to achieve a high porous product, and compare to spherical type. After SLS, the porosity of flake-type sample with 34% was quite higher than that of the spherical-type one that had only 11%. The surface roughness of the flake SLS sample were also investigated in both inner and surface parts. The results show that the deviation of the roughness of the surface part is about 64.40μm, while that of the internal one was about 117.65μm, which presents the containing of high porosity in the uneven surfaces. With the process using spherical powder, the sample was quite dense, however, some initial particles still remained as a result of less energy received at the beneath of the processing layer.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1215-1218
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
$SiO_x$ Nanowires Produced on Molybdenum-Coated Si Substrates
Autorzy:
Kim, H.
Lee, J.
Yang, J.
Powiązania:
https://bibliotekanauki.pl/articles/1813396.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
78.55.-m
Opis:
We synthesized $SiO_x$ nanowires with diameters of 30-140 nm, for the first time by the simple heating of the Mo-coated Si substrates. X-ray diffraction, selected area electron diffraction, and energy-dispersive X-ray spectroscopy indicated that the nanowires were in an amorphous state, comprising Si and O only. Fitting the photoluminescence spectrum with Gaussian functions revealed that the nanowires exhibited significant photoluminescence intensities near blue and green light regions. We extensively discussed the possible growth mechanism of $SiO_x$ nanowires.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 1017-1020
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
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:
User requirements supporting the safe navigation in Korean Coast
Autorzy:
Jeong, J.S.
Jeong, J.
Kim, H.J.
Kim, S. Y.
Powiązania:
https://bibliotekanauki.pl/articles/320412.pdf
Data publikacji:
2013
Wydawca:
Polskie Forum Nawigacyjne
Tematy:
user requirements
user needs
e-navigation
safe navigation
navigational information
Opis:
This research aims at investigating the user requirements at the service level for safe navigation system, following e-navigation strategy implementation plan. The user requirements is surveyed to collect real-time navigational information and then to find out services through the presentation of the collected information. To provide the information on user needs for the system developer, a questionnaire survey has been made. Based on this surveys, this research investigated which navigational information is with higher priority for the safe navigation during ship operation by bridge team in harbour and in coastal and confined.
W artykule przedstawiono wyniki badań wymagań użytkownika związanych z poziomem bezpieczeństwa nawigacji, stosownie do strategii wprowadzania e-nawigacji. Badano oczekiwania użytkowników odnośnie informacji nawigacyjnej dostarczanej w czasie rzeczywistym oraz sposobu jej prezentacji metodą ankietową. Wykonano przegląd kwestionariuszy dla ustalenia informacji o potrzebach użytkownika z myślą o projektantach systemów. Na bazie opisywanych badań ustalono, jakie informacje nawigacyjne cechują się najwyższym priorytetem w opinii użytkowników, zarówno w warunkach żeglugi przybrzeżnej, jak i w porcie lub akwenie ograniczonym.
Źródło:
Annual of Navigation; 2013, 20; 37-48
1640-8632
Pojawia się w:
Annual of Navigation
Dostawca treści:
Biblioteka Nauki
Artykuł
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:
Development of Carbon Nanotube Based Reflection Type X-ray Source
Autorzy:
Choi, H.
Kim, J.
Lee, C.
Powiązania:
https://bibliotekanauki.pl/articles/1807922.pdf
Data publikacji:
2009-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.47.Lx
75.47.Gk
73.50.Fq
Opis:
X-ray imaging technology is a useful and leading medical diagnostic tool for health care professionals to diagnose disease in human body. Carbon nanotube based X-ray source, which we have developed in this study, could be also useful and supply integrated diagnostic X-ray imaging tool in diagnosis. Conventionally, thermionic type of tungsten filament X-ray tube is widely employed in the field of biomedical and industrial application fields. However, intrinsic problems, such as poor emission efficiency, low imaging resolution, and high electrical energy consumption etc., may cause the limitation of using the X-ray tube. To fulfill the current market requirement, specifically for medical diagnostic field, we have developed rather a portable and compact carbon nanotube based X-ray device in which microfocus high imaging resolution can be feasible.
Źródło:
Acta Physica Polonica A; 2009, 115, 6; 1078-1080
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
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:
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:
Catalyst-Free Growth of Magnesium Oxide Whiskers and Their Characteristics
Autorzy:
Kim, H.
Kong, M.
Yang, J.
Powiązania:
https://bibliotekanauki.pl/articles/1813397.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
78.55.-m
Opis:
This study reports the production of magnesium oxide (MgO) whiskers on silicon (Si) substrates by the thermal heating of $MgB_2$ powders. We investigated the structural properties of the as-synthesized whiskers by using X-ray diffraction, transmission electron microscopy, selected area electron diffraction, and scanning electron microscopy. The product consisted of one-dimensional whiskers with a square cross-section. The whiskers had a single-crystalline cubic structure of MgO. The photoluminescence measurement with the Gaussian fitting exhibited visible light emission bands centered at 2.39 eV and 2.91 eV. We proposed the growth of MgO whiskers to follow the vapor-solid mechanism.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 1021-1024
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study on Effects of Mold Temperature on the Injection Molded Article
Autorzy:
Han, J.-H.
Kim, Y.-C.
Powiązania:
https://bibliotekanauki.pl/articles/351919.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
injection molding
mold temperature
cooling temperature
molded article
Opis:
This is a study of the effects of temperature of injection mold on the injection molded article. By supplying water of the proper temperature in the cooling line of mold in the cooling process, the mold was the appropriate temperature, and the deformation of the injection molded article was examined according to the mold temperature. In this study, we conducted simulation analysis and experiments, and the results were analyzed. The minimum deformation of the injection molded article model obtained by supplying 50°C water in the cooling line is 0.003 mm, and the maximum deformation was 0.813 mm. Injection molded article models obtained by supplying 20°C water were found to be a minimum of 0.002 mm, with deformation of up to 0.761 mm. When comparing both conditions, the error rate of injection molded article obtained by supplying 20°C water in the mold cooling line was lower by about 0.18%.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1271-1274
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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:
Synthesis, Structure, Photoluminescence, and Raman Spectrum of Indium Oxide Nanowires
Autorzy:
Kim, H.
Na, H.
Yang, J.
Lee,, C.
Powiązania:
https://bibliotekanauki.pl/articles/1505485.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.07.-b
78.55.-m
Opis:
Production of indium oxide $(In_2O_3)$ whiskers at a very low temperature of 650°C was reported. The synthetic route was comprised of a thermal heating process of a mixture of In and Mg powders. We have investigated the structural properties of the as-synthesized nanowires by using X-ray diffraction and scanning electron microscopy. The product consisted of one-dimensional nanowires, with a crystalline cubic structure of $In_2O_3$. The photoluminescence measurement with the Gaussian fitting exhibited visible light emission bands centered at 2.1 eV and 2.8 eV. The peaks of the Raman spectrum were indexed to the modes being associated with cubic $In_2O_3$.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 143-145
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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