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Wyświetlanie 1-8 z 8
Tytuł:
Analysis and Optimization of Micro Speaker-Box Using a Passive Radiator in Portable Device
Autorzy:
Jiang, Y.-W.
Kwon, J.-H.
Kim, H.-K.
Hwang, S.-M.
Powiązania:
https://bibliotekanauki.pl/articles/176530.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
passive radiator
speaker box
SPL improvement
Sound Pressure Level
Opis:
With the rapid development of multimedia devices such as smart phones and tablet PCs, microspeakers have been recently increasingly used for audio equipment. Improving the acoustic performance of a microspeaker is always a main concern, especially in the low frequency range. To avoid sound cancelation, a microspeaker unit is usually inserted into a speaker box. A passive radiator is also used in speaker boxes to improve the sound performance in the loudspeaker system. However, passive radiators have not been applied into microspeaker system. In this study, a speaker box with a passive radiator was analyzed and optimized to achieve a higher Sound Pressure Level (SPL) in a microspeaker system. The Finite Element Method (FEM), two-degree-of-freedom (DOF) vibration theory, and a plane circular piston sound source were used to study the electromagnetic, vibration, and acoustic characteristics, respectively. Optimization was conducted by changing the mass, stiffness, and size of the passive radiator. Based on the optimized parameters, a new sample was manufactured. The experiment results show that the SPL of the optimized speaker box with a passive radiator is improved by 5 dB at 200 Hz compared with the one without a radiator. The analysis results also matched the experiment results.
Źródło:
Archives of Acoustics; 2017, 42, 4; 753-760
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Grain Boundary Morphologies on Stress Corrosion Cracking of Alloy 600
Autorzy:
Kim, H. P.
Choi, M. J.
Kim, S. W.
Kim, D. J.
Lim, Y. S.
Hwang, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/352569.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
alloy 600
NaOH
stress corrosion cracking
grain boundary morphologies
Opis:
Effects of grain boundary morphologies on stress corrosion cracking (SCC) of Alloy 600 have been studied in 40% NaOH at 315°C using C-ring specimens. The configuration of the grain boundary and the intergranular carbide density were controlled by heat treatment. SCC tests were performed at +150 mV above the corrosion potential. The specimen with a serrated grain boundary showed higher SCC resistance than that with a straight grain boundary. This appears to be caused by the fact that the specimen with the serrated grain boundary has longer SCC path. SCC resistance also increased with intergranular carbide density probably due to enhanced relaxation of stress at intergranular carbide.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1415-1419
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fabrication of AZ31/CNT Surface Nano-composite by Double-pass Friction Stir Processing
Autorzy:
Kim, J. Y.
Hwang, J.-W.
Kim, H. Y.
Lee, S. M.
Jung, W.-S.
Byeon, J.-W.
Powiązania:
https://bibliotekanauki.pl/articles/355624.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surface modification
Double-pass Friction Stir Processing
AZ31
composite
CNT
Opis:
Double-pass Friction Stir Processing (FSP) was applied to fabricate an AZ31/CNT nano-composite for surface hardening of lightweight structural components. The effects of double-pass FSP as well as groove depth (i.e., volume fraction of CNT) on the CNT distribution, dynamically recrystallized grain size, and resulting microhardness were studied. Double-pass FSP was performed for the CNT-filled plate-type specimen with different groove depths of 2, 3, and 4 mm. By applying double-pass FSP, the average size of CNT clusters decreased, implying a more homogeneous distribution. Compared with the FSPed specimen without CNT, grain size was refined from 19 μm to 3 μm and microhardness increased from 52 Hv to 83 Hv (i.e., 71% increase).
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1039-1042
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxidation Behavior of Steel with Cr Content and Water Flow Rate
Autorzy:
Kim, D.-J.
Kim, K. M.
Shin, J. H.
Cheong, Y. M.
Lee, E. H.
Lee, G. G.
Kim, S. W.
Kim, H. P.
Choi, M. J.
Lim, Y. S.
Hwang, S. S.
Powiązania:
https://bibliotekanauki.pl/articles/351548.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steel
flow accelerated corrosion
Cr content
flow rate
surface oxides
Opis:
Fast water flow facilitates ferrous ion transport leading to flow accelerated corrosion (FAC) of carbon steel and the possibility of a large accident through a failure of a secondary pipe in a nuclear power plant. Ion transport is directly linked to oxide properties such as the thickness, chemical composition and porosity. This work deals with a precise observation of the cross section of the corroded specimen focusing on an oxide passivity and its thickness using SEM (scanning electron microscope) and TEM (transmission electron microscope) as well as an apparent weight loss and a surface observation for the specimens corroded using a rotating cylindrical electrode autoclave system in pure water of pH 7 at 150°C having dissolved oxygen below 1 ppb within a flow rate range of 0 to 10 m/s. The Cr content in steel was changed from 0.02 to 2.4 wt%. Increasing the Cr content in the alloy, the FAC rate and oxide thickness decreased. The oxide porosity tends to decrease with the Cr content and immersion time owing to the development of Cr containing oxide. The oxidation behavior is not changed with the immersion time.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1383-1387
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient Liquid Phase Behavior of Sn-Coated Cu Particles and Chip Bonding using Paste Containing the Particles
Autorzy:
Hwang, J. H.
Lee, J.-H.
Powiązania:
https://bibliotekanauki.pl/articles/353042.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Sn-coated Cu
immersion plating
chip bonding
intermetallic compounds (IMC)
transient liquid phase (TLP)
sintering
Opis:
Sn-coated Cu particles were prepared as a filler material for transient liquid phase (TLP) bonding. The thickness of Sn coating was controlled by controlling the number of plating cycles. The Sn-coated Cu particles best suited for TLP bonding were fabricated by Sn plating thrice, and the particles showed a pronounced endothermic peak at 232°C. The heating of the particles for just 10 s at 250°C destroyed the initial core-shell structure and encouraged the formation of Cu-Sn intermetallic compounds. Further, die bonding was also successfully performed at 250°C under a slight bonding pressure of around 0.1 MPa using a paste containing the particles. The bonding time of 30 s facilitated the bonding of Sn-coated Cu particles to the Au surface and also increased the probability of network formation between particles.
Źródło:
Archives of Metallurgy and Materials; 2017, 62, 2B; 1143-1148
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cr Poisoning On Nd2Ni0.95Cu0.05O4+δ Cathode for Solid Oxide Fuel Cells
Autorzy:
Choe, Y-J.
Lee, K. J.
Hwang, H-J.
Powiązania:
https://bibliotekanauki.pl/articles/354728.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chromium poisoning
Ruddlesden-Popper
layered perovskite
solid oxide fuel cells
Nd2NiO4
Opis:
In this study, Nd2Ni1-xCuxO4+δ (x=0, 0.05, 0.1, and 0.2) layered perovskite powders were synthesized by the glycine nitrate process (GNP) and the chromium poisoning effect on the electrochemical performance of the Nd2Ni0.95Cu0.05O4+δ and La0.6Sr0.4Co0.2Fe0.88O3-δ cathodes were investigated. In the case of the LSCF cathode, the strontium chromite phase formed after the exposure of the gaseous chromium species, while there was no additional phase in the Nd2Ni0.95Cu0.05O4+δ cathode. The area specific resistance (ASR) of the Nd2Ni0.95Cu0.05O4+δ cathode did not change significantly after the exposure of the gaseous chromium species at 800°C
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 629-634
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of Copper Doped Neodymium Nickelate Oxide as Cathode Material for Solid Oxide Fuel Cells
Autorzy:
Lee, K. J.
Choe, Y-J.
Hwang, H-J.
Powiązania:
https://bibliotekanauki.pl/articles/351292.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
solid oxide fuel cells
copper
electrical conductivity
excess oxygen
Opis:
Mixed ionic and electronic conducting K2NiF4-type oxide, Nd2Ni1-xCuxO4+δ (x=0~1) powders were synthesized by solid state reaction technique and solid oxide fuel cells consisting of a Nd2Ni1-xCuxO4+δ cathode, a Ni-YSZ anode and ScSZ as an electrolyte were fabricated. The effect of copper substitution for nickel on the electrical and electrochemical properties was examined. Small amount of copper doping (x=0.2) resulted in the increased electrical conductivity and decreased polarization resistance. It appears that this phenomenon was associated with the high mean valence of nickel and copper and the resulting excess oxygen (δ). It was found that power densities of the cell with the Nd2Ni1-xCuxO4+δ (x=0.1 and 0.2) cathode were higher than that of the cell with theNd2NiO4+δ cathode.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 2A; 625-628
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Argon Plasma in a New Process for Improving the Physical and Anti-bacterial Properties of Crosslinked Cotton Cellulose with Dimethyloldihydroxyethyleneurea-Maleic Acid
Zastosowanie plazmy niskotemperaturowej w środowisku argonu w procesie obróbki tkanin bawełnianych sieciowanych za pomocą kwasu dimetylodihydroxyetylenourylomaleinowego dla polepszenia właściwosci fizycznych oraz antybakteryjnych
Autorzy:
Tsou, C H
Suen, M C
Tsou, C Y
Chen, J C
Yeh, J T
Lin, S M
Lai, Y C
Hwang, J Z
Huang, S H
Hung, W S
Hu, C C
Lee, K R
Lai, J Y
Powiązania:
https://bibliotekanauki.pl/articles/232331.pdf
Data publikacji:
2015
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Biopolimerów i Włókien Chemicznych
Tematy:
cotton
plasma
antibacterial
crosslinking
crosslink length
crosslinks number per anhydroglucose
surface distribution
odour absorption
bawełna
plazma
właściwości antybakteryjne
sieciowanie tkanin bawełnianych
kwas dimetylodihydroxyetylenourylomaleinowy
odporności na zagniecenia
pochłanianie zapachów
żywica termoutwardzalna
Opis:
This study reports the findings of an argon (Ar) plasma treatment added to the traditional pad-dry-cure process between dry and cure treatments. This new process is called the "paddry-plasma-cure process". The crosslinking agent was a mixture of dimethyloldihydroxyethyleneurea (DMDHEU) and maleic acid (MA). Results show that Ar plasma treatment can increase the bonded crosslinking agent (i.e., the nitrogen content). The dry crease recovery angle (DCRA), wet crease recovery angle (WCRA), and tensile strength retention (TSR) of the pad-dry-plasma-cure finished fabrics were higher than those of traditional pad-dry-cure finished fabrics at a given nitrogen content. Additionally it was found that the number of crosslinks per anhydroglucose unit (CL/AGU) and the length of crosslinks of pad-dry-plasma-cure-finished fabrics were higher than that of traditional pad-dry-cure finished fabrics at the same resin concentration in the pad bath. DCRA, WCRA and TSR values of pad-dry-plasma-cure-finished fabrics were higher than those of pad-dry-curefinished fabrics at the same CL/AGU value. However, activation energies for the pad-dryplasma-cure process were higher than those for the pad-dry-cure process. The anti-bacterial ability and odour absorption of the pad-dry-plasma-cure and pad-dry-plasma-cure finished fabrics were higher than those for the pad-dry-cure finished fabrics. The surface distribution of crosslinking agents for the pad-dry-plasma-cure process was higher than that of the pad-dry-cure process. Thus the pad-dry-plasma-cure process is excellent for improving the physical properties, bacterial inhibition, and odour absorption of finished cotton fabrics and for decreasing their formaldehyde release.
Artykułu odnosi się do problematyki możliwości i celowości wprowadzenia modyfikacji plazmowej w warunkach niskociśnieniowych i w środowisku argonu do konwencjonalnego procesu wykończenia przeciw mnącego z zastosowaniem reaktywnych żywic termoutwardzalnych. Badano kąt odprężenia na sucho i na mokro, i stwierdzono polepszenie właściwości odporności na zagniecenia w wyniku dodatkowego zastosowania plazmy. Badano również właściwości antybakteryjne i pochłanianie zapachów, które okazały się korzystniejsze dla dodatkowej obróbki plazmowej. W wyniku zmodyfikowanej obróbki uzyskano mniejsze wydzielanie formaldehydu z gotowej tkaniny.
Źródło:
Fibres & Textiles in Eastern Europe; 2015, 1 (109); 49-56
1230-3666
2300-7354
Pojawia się w:
Fibres & Textiles in Eastern Europe
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-8 z 8

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