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Wyszukujesz frazę "Kim, C." wg kryterium: Autor


Tytuł:
Comparison of soil CO2 efflux rates in Larix leptolepis, Pinus densiflora and P. rigitaeda plantations in southern Korea
Autorzy:
Kim, C.
Jeong, J.
Powiązania:
https://bibliotekanauki.pl/articles/41331.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
soil
carbon dioxide
efflux system
Larix leptolepis
Pinus densiflora
Pinus rigida
carbon cycling
carbon dynamics
root decomposition
soil respiration
plantation
Korea
Opis:
This study compared soil CO2 efflux rates in three adjacent coniferous plantations consisting of larch (Larix leptolepis Gordon), red pine (Pinus densiflora S. et Z.) and rigitaeda pine (P. rigitaeda: P. rigida Mill × P. taeda L.) species planted in the same year (1963). Soil CO2 efflux, litter fall carbon (C) and root decomposition rates were measured with soil environmental factors for two years. The mean annual soil CO2 efflux rates (g CO2 m−2 hour−1) were the highest in rigitaeda pine (0.30), followed by red pine (0.27) and larch (0.24) plantations. An exponential regression of the CO2 efflux rates against their corresponding soil temperatures showed a significant (P < 0.05) relationship (red pine R2 = 0.69; rigitaeda pine R2 = 0.67; larch R2 = 0.63). The soil CO2 efflux rates were negatively correlated with soil pH, but the soil water and soil organic C content were not significantly correlated with the CO2 efflux rates. Soil CO2-C efflux rates were correlated by litter fall C inputs in the larch and red pine plantations, and the decomposition rates of 5–10 mm diameter roots in the larch plantation. This result is useful in understanding potential responses of soil CO2 efflux rates with changes in stand and soil environmental factors induced by different tree species.
Źródło:
Dendrobiology; 2016, 76
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A queueing system with heterogeneous impatient customers and consumable additional items
Autorzy:
Baek, J.
Dudina, O.
Kim, C.
Powiązania:
https://bibliotekanauki.pl/articles/907646.pdf
Data publikacji:
2017
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
marked Markovian arrival process
consumable additional items
phase type distribution
impatient customer
Markowski proces zgłoszeń
system kolejkowy
rozkład fazowy
klient niecierpliwy
Opis:
A single-server queueing system with a marked Markovian arrival process of heterogeneous customers is considered. Type-1 customers have limited preemptive priority over type-2 customers. There is an infinite buffer for type-2 customers and no buffer for type-1 customers. There is also a finite buffer (stock) for consumable additional items (semi-products, half-stocks, etc.) which arrive according to the Markovian arrival process. Service of a customer requires a fixed number of consumable additional items depending on the type of the customer. The service time has a phase-type distribution depending on the type of the customer. Customers in the buffer are impatient and may leave the system without service after an exponentially distributed amount of waiting time. Aiming to minimize the loss probability of type-1 customers and maximize throughput of the system, a threshold strategy of admission to service of type-2 customers is offered. Service of type-2 customer can start only if the server is idle and the number of consumable additional items in the stock exceeds the fixed threshold. Stationary distributions of the system states and the waiting time are computed. In the numerical example, we show some interesting effects and illustrate a possibility of application of the presented results for solution of optimization problems.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2017, 27, 2; 367-384
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of an MMAP/PH1, PH2/N/∞ queueing system operating in a random environment
Autorzy:
Kim, C.
Dudin, A.
Dudin, S.
Dudina, O.
Powiązania:
https://bibliotekanauki.pl/articles/330607.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
random environment
marked Markovian arrival process
phase type distribution
Laplace–Stieltjes transform
rozkład fazowy
transformata Laplace'a-Stieltjesa
system operacyjny
system kolejkowy
Opis:
A multi-server queueing system with two types of customers and an infinite buffer operating in a random environment as a model of a contact center is investigated. The arrival flow of customers is described by a marked Markovian arrival process. Type 1 customers have a non-preemptive priority over type 2 customers and can leave the buffer due to a lack of service. The service times of different type customers have a phase-type distribution with different parameters. To facilitate the investigation of the system we use a generalized phase-type service time distribution. The criterion of ergodicity for a multi-dimensional Markov chain describing the behavior of the system and the algorithm for computation of its steady-state distribution are outlined. Some key performance measures are calculated. The Laplace–Stieltjes transforms of the sojourn and waiting time distributions of priority and non-priority customers are derived. A numerical example illustrating the importance of taking into account the correlation in the arrival process is presented.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2014, 24, 3; 485-501
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bringing Kano’s perspective to AHP: the 2D-AHP decision model
Autorzy:
Jung, U.
Yim, S.
Lim, S.
Kim, C.
Powiązania:
https://bibliotekanauki.pl/articles/407247.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analytic hierarchy process (AHP)
Kano model
hybrid model
multicriteria decision making
two dimension perspective
Opis:
AHP and the Kano model are such prevalent TQM tools that it may be surprising that a true hybrid decision-making model has so far eluded researchers. The quest for a hybrid approach is complicated by the differing output perspective of each model, namely discrete ranking (AHP) versus a multi-dimensional picture (Kano). This paper presents a hybrid model of AHP and Kano model, so called two-dimension AHP (2D-AHP). This paper first compares the two approaches and justifies a hybrid model based on a simple conceit drawn from the Kano perspective: given a decision hierarchy, child and parent elements can exhibit multi-dimension relationships under different circumstances. Based on this premise, the authors construct a hybrid two-dimension AHP model whereby a functionaldysfunctional question-pair technique is incorporated into a traditional AHP framework. Using the proposed hybrid model, this paper provides a practical test case of its implementation. The 2D-AHP approach revealed important evaluation variances obscured through AHP, while a survey study confirmed that the 2D-AHP approach is both feasible and preferred in some respects by respondents. Although there have been rich research efforts to combine AHP and Kano model, most of them is simply about a series of individual usage of each methodology. On the other hand, the type of hybridization between AHP and Kano model in this paper is quite unique in terms of the two dimensional perspective. The model provides a general approach with application possibilities far beyond the scope of the test case and its problem structure, and so calls for application and validation in new cases.
Źródło:
Management and Production Engineering Review; 2016, 7, 4; 16-26
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
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:
Novel Extraction Process Of Rare Earth Elements From NdFeB Powders Via Alkaline Treatment
Nowy sposób ekstrakcji pierwiastków ziem rzadkich z proszków NdFeB w roztworach alkalicznych
Autorzy:
Chung, K. W.
Kim, C.-J.
Yoon, H.-S.
Powiązania:
https://bibliotekanauki.pl/articles/355324.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
recycling
NdFeB magnet
alkaline treatment
leaching
selective leaching efficiency
recykling
magnes neodymowy
obróbka alkaliczna
ługowanie
wydajność
Opis:
The alkaline treatment of NdFeB powders in NaOH solution at various equivalent amounts of NaOH at 100°C was performed. The resultant powders were then leached in 0.5M H2SO4 solution at 25°C for 2 minutes. At 5 equivalents of NaOH, neodymium in NdFeB powders was partially transformed to neodymium hydroxide. The transformation of neodymium to neodymium hydroxide actually occurred at 10 equivalents of NaOH and was facilitated by increasing the equivalent of NaOH from 10 to 30. In addition, iron was partially transformed to magnetite during the alkaline treatment, which was also promoted at a higher equivalent of NaOH. The leaching yield of neodymium from alkaline-treated powders was increased with an increasing equivalent of NaOH up to 10; however, it slightly decreased with the equivalent NaOH of over 10. The leaching yield of iron was inversely proportional to that of rare earth elements. NdFeB powders treated at 10 equivalents of NaOH showed a maximum leaching yield of neodymium and dysprosium of 91.6% and 94.6%, respectively, and the lowest leaching yield of iron of 24.2%, resulting in the highest selective leaching efficiency of 69.4%.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1301-1305
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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:
A Study On Dispersion Stability Of Nickel Nanoparticles Synthesized By Wire Explosion In Liquid Media
Badanie stabilności dyspersji nanocząstek niklu wytworzonych metodą WEP w ciekłym medium
Autorzy:
Kim, C. K.
Lee, G.-J.
Lee, M. K.
Rhee, C. K.
Powiązania:
https://bibliotekanauki.pl/articles/356909.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
nickel nanofluid
pulsed wire evaporation
surfactant
zeta potential
dispersion stability
nanocząstka niklu
środek powierzchniowo czynny
stabilność dyspersji
potencjał zeta
dyspersja
Opis:
In this study, nickel nanoparticles were synthesized in ethanol using portable pulsed wire evaporation, which is a one-step physical method. From transmission electron microscopy images, it was found that the Ni nanoparticles exhibited a spherical shape with an average diameter of 7.3 nm. To prevent aggregation of the nickel nanoparticles, a polymer surfactant was added into the ethanol before the synthesis of nickel nanoparticles, and adsorbed on the freshly synthesized nickel nanoparticles during the wire explosion. The dispersion stability of the prepared nickel nanofluids was investigated by zeta-potential analyzer and Turbiscan optical analyzer. As a result, the optimum concentration of polymer surfactant to be added was suggested for the maximized dispersion stability of the nickel nanofluids.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1379-1382
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Analysis Of Stress Intensity Factor Due To Normal Stress For A Cracked Plate Reinforced With A Sheet By Seam Welding
Analiza współczynnika intensywności naprężeń wynikających z prostopadłego naprężenia dla pękniętej płyty wzmocnionej płytą przyspawaną szwem
Autorzy:
Kim, O.-H.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/352434.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stress intensity factor
seam welding
singular integral equation
reinforcement effect
współczynnik intensywności naprężeń
spawanie
efekt wzmacniający
Opis:
It is essential in damage tolerance design to determine the stress intensity factor theoretically. The stress intensity factor for a cracked plate that is reinforced with a sheet by seam welding is determined theoretically and plotted as function of the seam welding location and stiffness ratio. The singular integral equation is derived based on the compatibility condition between the cracked plate and the reinforcement plate, and it is solved by means of Erdogan and Gupta‘s method. The theory is verified by comparing the results of the present analysis with those of a numerical analysis. The results from the present analysis show that the reinforcement effect improves as the welding line is situated closer to the crack and as the stiffness ratio of the cracked plate and the reinforcement plate increases.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1441-1444
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study Of The Die Roll Height Of SHP-1 And SCP-1 Materials In The Fine Blanking Process
Badanie wysokości deformacji krawędzi wycinanych elementów ze stali SHP-1 i SCP-1 procesie wykrawania
Autorzy:
Lee, C. K.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/356499.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
die roll
fine blanking
SCP-1
share speed
SHP-1
v-rings
krawędzie
wykrawanie
szybkość działania
deformacja
Opis:
The height of the die roll, the distance of the V-ring, and the shear rate were varied with the aim of investigating the effects of the applied changes on the fine blanking line in a cold-rolled and a pickled steel sheet, referred to as SCP-1 and SHP-1, respectively. Both materials consisted primarily of a ferrite phase with small amounts of impurities including F, Mn, and Cr. The distance was found to be a very important factor in controlling the shear of the V-ring in the fine blanking process. When the position of the V-ring was set at distances of 1.5 mm and 2 mm, the die roll height increased with increasing shear speeds from 6.4 m/min to 10 and 16 m/min. Analysis of the influence of the shear rate revealed that low rates resulted in the lowest die roll heights since the flow of material was effectively inhibited.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1397-1402
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study on Changes in Thickness of STS304 Material in the Progressive Drawing Process
Autorzy:
Lee, C. K.
Kim, Y. C.
Powiązania:
https://bibliotekanauki.pl/articles/356710.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
body thickness
drawing
flange thickness
corner roundness
material thickness
Opis:
In the drawing process, the roundness of corners in the punch and the die are very important factors in determining the thicknesses of the product. The results clearly revealed that the thickness of a flange was increased and the thickness of body parts reduced when the roundness of the die entrance was small. The material thickness of the top part was decreased when the corner roundness of the punch was large. The smooth inflow of materials was found to have a significant effect on the thickness during the post-process. The compressive strength of STS 304 material exhibited a higher value compared with other processing methods. Moreover, we clearly observed the corner roundness of the punch and the die to be a very important factor for STS 304 materials.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1319-1323
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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:
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:
Fabrication of Antireflection Structures as a Protective Layer of Solar Cells with Nanoporous Silica Films and Nanoimprinted Moth-Eye Structure
Autorzy:
Kim, K.
Han, J.
Jang, J.
Choi, C.
Choi, S.
Kim, C.
Kye, H.
Cheong, I.
Powiązania:
https://bibliotekanauki.pl/articles/1492625.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.-w
68.37.-d
68.55.-a
78.20.-e
Opis:
The antireflection structures are fabricated by sol-gel process as a protective layer of solar cells and by hot embossing process with anodized aluminum oxide membrane template on polycarbonate film. The optical properties and morphology of the antireflection structures are analyzed by UV-visible spectroscopy and field emission scanning electron microscopy, respectively. The total conversion efficiency of a polycrystalline Si solar cell module with the protective layer, sol-gel-derived nanoporous antireflection structure, is increased by 2.6% and 5.7% for one-side antireflection coated prismatic matt glass and both-side antireflection coated prismatic matt glass, respectively.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-047-A-049
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A study of the local entropy generation rate in a porous media burner
Autorzy:
Mohammadi, I.
Esfahani, J. A.
Kim, K. C.
Powiązania:
https://bibliotekanauki.pl/articles/38597672.pdf
Data publikacji:
2020
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
porous media burner
chemical kinetics
volumetric heat transfer
axisymmetric combustion
local entropy generation
excess air ratio
Opis:
In this paper, the work and performance of the premixed methane-air porous axisymmetrical burner have firstly been simulated numerically using the CFD tools. For this purpose the set of governing equations has been enriched by an additional energy equation in porous solid, and the chemical species transport has been extended onto the multi-step mechanism (GRI-2-11). This numerical model has been verified on the base of available benchmark experiments. Next, we have studied the local entropy generation problem taking into account not only classical contributions like viscous and turbulent dissipation but also, the porous combustion of gases. The results showed that the greatest portion of entropy generation in the porous medium burner is related to chemical reactions, followed by heat transfer, mass diffusion (mixing) and friction (viscous dissipation), respectively. According to the results, as the excess air ratio increases, the local entropy generation rate due to heat transfer and friction increases and the local entropy generation rate due to chemical reactions is decreased. Also, by increasing the volumetric heat transfer coefficient, the local entropy generation rate due to heat transfer decreases and the local entropy generation rate due to friction and chemical reactions increases. Also, the local entropy generation rate due to mixing does not show a significant change with the changing excess air ratio and volumetric heat transfer coefficient.
Źródło:
Archives of Mechanics; 2020, 72, 3; 257-279
0373-2029
Pojawia się w:
Archives of Mechanics
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:
Experimental Study On Fracture Property Of Tapered Double Cantilever Beam Specimen With Aluminum Foam
Doświadczalne badanie pękania mimośrodowo rozciąganej zwężanej próbki z bocznym karbem wykonanej z piany aluminiowej
Autorzy:
Kim, Y. C.
Kim, S. S.
Cho, J. U.
Powiązania:
https://bibliotekanauki.pl/articles/352697.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminum foam
tapered double cantilever beam (TDCB)
fracture behavior
adhesively bonded structures
adhesive fracture energy
piana aluminiowa
pękanie
stożkowa podwójna belka wspornikowa
struktura sklejona
Opis:
It is indispensable to evaluate fracture energy as the bonding strength of adhesive at composite material with aluminum foam. This specimen is designed with tapered double cantilever beam by British standards (BS 7991 and ISO 11343). 4 kinds of specimens due to m values of 2, 2.5, 3 and 3.5 are manufactured and compared each other with the experimental results. Adhesive fracture energy is calculated from the formulae of British standards. The value of m is the gradient which is denoted as the length and the height of specimen. As m becomes greater at static experimental result, the maximum load becomes higher and the displacement becomes lower. And the critical fracture energy becomes higher. As m becomes less at fatigue experimental result, the displacement becomes higher and the critical fracture energy becomes higher. Fracture behavior of adhesive can be analyzed by this study and these experimental results can be applied into real field effectively. The stability on TDCB structure bonded with aluminum foam composite can be predicted by use of this experimental result. Adhesive fracture energy is calculated from the formulae of British standards. Based on correlations obtained in this study, the fracture behavior of bonded material would possibly be analyzed and aluminum foam material bonded with adhesive would be applied to a composite structure in various fields, thereby analyzing the mechanical and fracture characteristic of the material.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1459-1462
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental Study On Fracture Property Of Double Cantilever Beam Specimen With Aluminum Foam
Doświadczalne badanie pękania mimośrodowo rozciąganej próbki z bocznym karbem wykonanej z piany aluminiowej
Autorzy:
Kim, Y. C.
Choi, H. K.
Cho, J. U.
Powiązania:
https://bibliotekanauki.pl/articles/351465.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aluminium foam
double cantilever beam
fracture energy
adhesively bonded structure
piana aluminiowa
podwójna belka wspornikowa
energia pękania
Opis:
This study aims to investigate double cantilever beam specimen with aluminum foam bonded by spray adhesive to investigate the fracture strength of the adhesive joint experimentally. The fracture energy at opening mode is calculated by the formulae of British Engineering Standard (BS 7991) and International Standard (ISO 11343). For the static experiment, four types of specimens with the heights (h) of 25 mm, 30 mm, 35 mm and 40 mm are manufactured and the experimental results are compared with each other. As the height becomes greater, the fracture energy becomes higher. After the length of crack reaches 150 mm, the fracture energy of the specimen (h=35 mm) is greater than that of the specimen (h=40 mm). Fatigue test is also performed with DCB test specimen. As the height decreases, the fracture energy becomes higher. By the result obtained from this study, aluminum foam with adhesive joint can be applied to actual composite structure and its fracture property can possibly be anticipated.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1151-1154
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect Of Different Mechanical Milling Processes On Morphology And Microstructural Changes Of Nano And Micron Al-Powders
Wpływ różnych procesów mielenia na morfologię i mikrostrukturę nanometrycznych i mikronowych proszków Al
Autorzy:
Kim, H.-S.
Madavali, B.
Eom, T.-J.
Kim, C.- M.
Koo, J.-M.
Lee, T. H.
Hong, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/355715.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al alloys
high-energy ball milling
low energy ball milling
plastic deformation
stopy Al
wysokoenergetyczne mielenie kulkowe
mielenie energooszczędne
odkształcenia plastyczne
Opis:
In this research, effect of the various mechanical milling process on morphology and microstructural changes of nano and micron Al-powders was studied. The milling of Al-powders was performed by both high energy and low energy ball milling process. The influence of milling (pulverizing) energy on the structural changes of Al-powders was studied. Al-nanoparticles were agglomerated during the MA and its size was increased with increasing milling while micron Al-powder gets flattened shape during high energy ball milling due to severe plastic deformation. Meanwhile, structural evolution during high energy ball milling of the nano powder occurred faster than that of the micron powder. A slight shift in the position of X-ray diffraction peaks was observed in nano Al-powders but it was un-altered in macro Al-powders. The variation in lattice parameters was observed only for nano Al powders during the high energy ball milling due to lattice distortion.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 2B; 1235-1239
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Acid Dissolution Conditions on Recovery of Valuable Metals from Used Plasma Display Panel Scrap
Autorzy:
Kim, C.- M.
Dharmaiah, P.
Kim, H.-S.
Koo, J.-M.
Yoon, J.-S.
Hong, S.-H.
Hong, S.-J.
Powiązania:
https://bibliotekanauki.pl/articles/355713.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
high energy ball milling
waste plasma display panels
dissolution
recovery
Opis:
The objective of this particular study was to recover valuable metals from waste plasma display panels using high energy ball milling with subsequent acid dissolution. Dissolution of milled (PDP) powder was studied in HCl, HNO3, and H2SO4 acidic solutions. The effects of dissolution acid, temperature, time, and PDP scrap powder to acid ratio on the leaching process were investigated and the most favorable conditions were found: (1) valuable metals (In, Ag, Mg) were recovered from PDP powder in a mixture of concentrated hydrochloric acid (HCl:H2O = 50:50); (2) the optimal dissolution temperature and time for the valuable metals were found to be 60°C and 30 min, respectively; (3) the ideal PDP scrap powder to acid solution ratio was found to be 1:10. The proposed method was applied to the recovery of magnesium, silver, and indium with satisfactory results.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1173-1177
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication and Characterization of Ni-CNT Composites by Electrical Explosion of Wire in Different Liquids
Autorzy:
Thuyet-Nguyen, M.
Maithili-Biswas, Maithili-Biswas
Kim, W. J.
Kim, J.-C.
Powiązania:
https://bibliotekanauki.pl/articles/958201.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Nickel-Carbon nanotubes composite
carbon nanotubes
electrical explosion of wire
nano-colloid
magnetic properties
Opis:
In this study, Ni-CNT powders and colloids were synthesized via the Electrical explosion of wire (EEW) in different liquid conditions. The influence of ambient solvents (D.I. Water, ethanol, methanol, acetone and ethylene-glycol) on characteristics of the as-synthesized Ni-CNT was investigated. The morphology and size were observed by field emission scanning electron microscopy (FE-SEM). The Ni particles were spherical or near spherical shape. The phase of the composite powders analyzed via X-ray diffraction demonstrate the presence of CNTs in composite powders is not affect the structure of Ni. However, the phase of the composites was changed based on the changing of liquid conditions. Stability of colloids was investigated by Turbiscan technique. Magnetic properties were also investigated by Vibrating sample magnetometer (VSM) at room temperature. The as-synthesized composite powders revealed a ferromagnetic characteristic material.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1219-1223
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Heat Treatment on Microstructure and Impact Toughness of Ti-6Al-4V Manufactured by Selective Laser Melting Process
Autorzy:
Lee, K.-A.
Kim, Y.-K.
Yu, J.-H.
Park, S.-H.
Kim, M.-C.
Powiązania:
https://bibliotekanauki.pl/articles/354570.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
selective laser melting
Ti-6Al-4V
microstructure
impact toughness
heat treatment
Opis:
This study manufactured Ti-6Al-4V alloy using one of the powder bed fusion 3D-printing processes, selective laser melting, and investigated the effect of heat treatment (650°C/3hrs) on microstructure and impact toughness of the material. Initial microstructural observation identified prior-β grain along the building direction before and after heat treatment. In addition, the material formed a fully martensite structure before heat treatment, and after heat treatment, α and β phase were formed simultaneously. Charpy impact tests were conducted. The average impact energy measured as 6.0 J before heat treatment, and after heat treatment, the average impact energy increased by approximately 20% to 7.3 J. Fracture surface observation after the impact test showed that both alloys had brittle characteristics on macro levels, but showed ductile fracture characteristics and dimples at micro levels.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1341-1346
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
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:
Effect of Trace Elements (Co, Cr) on the Microstructure and Physical Properties of Al-Si-Cu-Mg-Fe Extruded Alloy
Autorzy:
Ahn, S. S.
Sharief, P.
Lee, C. H.
Son, H. T.
Kim, Y. H.
Kim, Y. C.
Hong, S.
Hong, S. J.
Powiązania:
https://bibliotekanauki.pl/articles/352787.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al-Si alloy
microstructure
extrusion
coefficient of thermal expansion
trace elements
Opis:
Trace elements Co, Cr were added to investigate their influence on the microstructure and physical properties of Al-Si extruded alloy. The Co, Cr elements were randomly distributed in the matrix, forms intermetallic phase and their existence wereconfirmed by XRD, EDS and SEM analysis. With addition of trace elements, the microstructure was modified, Si particle size was reduced and the growth rate of β-(Al5 FeSi) phase limited. Compared to parent alloy, hardness and tensile strength were enhanced while the linear coefficient of thermal expansion (CTE) was significantly reduced by 42.4% and 16.05% with Co and Cr addition respectively. It is considered that the low CTE occurs with addition of Co was due to the formation of intermetallic compound having low coefficient of thermal expansion. The results suggested that Co acts as an effective element in improving the mechanical properties of Al-Si alloy.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 3; 857-862
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Localized Electric Field in the Type-II InAs/GaAsSb/GaAs Structure
Autorzy:
Lee, S.
Kim, J.
Yoon, S.
Kim, Y.
Honsberg, C.
Powiązania:
https://bibliotekanauki.pl/articles/1398577.pdf
Data publikacji:
2016-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Fd
78.40.-q
73.40.Lq
73.50.Pz
Opis:
The effect of localized electric field (F) was investigated in the type-II InAs/GaAsSb/GaAs structures. To compare type-I to type-II, two types of samples with different Sb contents was grown by molecular beam epitaxy, whose Sb contents are 3% (type-I) and 16% (type-II), respectively. In the both samples, we performed excitation power dependent-photoreflectance at 10 K and the result showed that the period of the Franz-Keldysh oscillation, revealed above the band gap $(E_{g})$ of GaAs, was broadened in the only type-II system, which means that F was also increased because it is proportional to the period of the Franz-Keldysh oscillation while the period of the Franz-Keldysh oscillations stayed unchanged in type-I system. This phenomenon is explained by that the F was affected by the band bending effect caused by the spatially separated photo-excited carriers in the interface between GaAsSb and GaAs. The F changed linearly as a function of square root of excitation power as expected for the F. Moreover, F was calculated using fast Fourier transform method for a qualitative analysis, which is in a good agreement with the theory of triangular well approximation.
Źródło:
Acta Physica Polonica A; 2016, 130, 5; 1213-1216
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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