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Wyszukujesz frazę "Yeh, J." wg kryterium: Autor


Wyświetlanie 1-5 z 5
Tytuł:
Fading Statistics in Communications - a Random Matrix Approach
Autorzy:
Yeh, J.
Ott, E.
Antonsen, T.
Anlage, S.
Powiązania:
https://bibliotekanauki.pl/articles/1492740.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Sq
05.45.Mt
42.25.Dd
78.20.Bh
Opis:
Fading is the time-dependent variations in signal strength measured at a receiver, due to temporally evolving multipath scattering and interference. In our previous work we introduced a statistical fading model for the time-reversal invariant case by combining the predictions of random matrix theory with the random coupling model that includes system-specific properties such as the radiation impedance of the ports and short-orbit effects. In the high-loss limit this random matrix theory model reduced to the most common fading models in the wireless communication field. In this paper we discuss the theoretical model in more detail and extend it to the case of broken time-reversal invariance.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-085-A-088
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Impedance and Scattering Variance Ratios of Complicated Wave Scattering Systems in the Low Loss Regime
Autorzy:
Yeh, J.
Drikas, Z.
Gil Gil, J.
Hong, S.
Taddese, B.
Ott, E.
Antonsen, T.
Andreadis, T.
Anlage, S.
Powiązania:
https://bibliotekanauki.pl/articles/1399042.pdf
Data publikacji:
2013-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.45.Mt
24.60.-k
42.25.Dd
78.20.Bh
Opis:
Random matrix theory successfully predicts universal statistical properties of complicated wave scattering systems in the semiclassical limit, while the random coupling model offers a complete statistical model with a simple additive formula in terms of impedance to combine the predictions of random matrix theory and nonuniversal system-specific features. The statistics of measured wave properties generally have nonuniversal features. However, ratios of the variances of elements of the impedance matrix are predicted to be independent of such nonuniversal features and thus should be universal functions of the overall system loss. In contrast with impedance variance ratios, scattering variance ratios depend on nonuniversal features unless the system is in the high loss regime. In this paper, we present numerical tests of the predicted universal impedance variance ratios and show that an insufficient sample size can lead to apparent deviation from the theory, particularly in the low loss regime. Experimental tests are carried out in three two-port microwave cavities with varied loss parameters, including a novel experimental system with a superconducting microwave billiard, to test the variance-ratio predictions in the low loss time-reversal-invariant regime. It is found that the experimental results agree with the theoretical predictions to the extent permitted by the finite sample size.
Źródło:
Acta Physica Polonica A; 2013, 124, 6; 1045-1052
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Assessment of a One-Mass Spring-Based Electromagnetic Energy Harvester on a Vibrating Object
Autorzy:
Chiu, M.-C.
Chang, Y.-C.
Yeh, L.-J.
Chung, C.-H.
Powiązania:
https://bibliotekanauki.pl/articles/177720.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spring
harvester
generator
permanent magnet
simulated annealing
optimization
buckling
Fatigue
Opis:
The paper is an exploration of the optimal design parameters of a space-constrained electromagnetic vibration-based generator. An electromagnetic energy harvester is composed of a coiled polyoxymethylen circular shell, a cylindrical NdFeB magnet, and a pair of helical springs. The magnet is vertically confined between the helical springs that serve as a vibrator. The electrical power connected to the coil is actuated when the energy harvester is vibrated by an external force causing the vibrator to periodically move through the coil. The primary factors of the electrical power generated from the energy harvester include a magnet, a spring, a coil, an excited frequency, an excited amplitude, and a design space. In order to obtain maximal electrical power during the excitation period, it is necessary to set the system’s natural frequency equal to the external forcing frequency. There are ten design factors of the energy harvester including the magnet diameter (Dm), the magnet height (Hm), the system damping ratio (ζsys), the spring diameter (Ds), the diameter of the spring wire (ds), the spring length (ℓs), the pitch of the spring (ps), the spring’s number of revolutions (Ns), the coil diameter (Dc), the diameter of the coil wire (dc), and the coil’s number of revolutions (Nc). Because of the mutual effects of the above factors, searching for the appropriate design parameters within a constrained space is complicated. Concerning their geometric allocation, the above ten design parameters are reduced to four (Dm, Hm, ζsys, and Nc). In order to search for optimal electrical power, the objective function of the electrical power is maximized by adjusting the four design parameters (Dm, Hm, ζsys, and Nc) via the simulated annealing method. Consequently, the optimal design parameters of Dm, Hm, ζsys, and Nc that produce maximum electrical power for an electromagnetic energy harvester are found.
Źródło:
Archives of Acoustics; 2016, 41, 1; 119-131
0137-5075
Pojawia się w:
Archives of Acoustics
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
Tytuł:
Investigation on Stripping-down TNT from Waste Munitions by Supercritical CO2 Fluid Extraction under Low Temperature Conditions
Autorzy:
Yang, T.-M.
Li, J.-S.
Su, C.-S.
Lu, K.-T.
Yeh, T.-F.
Powiązania:
https://bibliotekanauki.pl/articles/358681.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
treatment of waste munitions
supercritical fluid extraction technique
TNT
stripping-down
low temperature conditions
Opis:
The traditional methods of waste munitions treatment are expensive and also have potential risks during the treatment process. The supercritical fluid extraction technique has been a rapidly developing technique in the chemical industry in recent years. CO2 is used as the solvent, which has some advantages, such as low pollution, low cost, good chemical stability and can be operated under low temperature conditions. This research explored the feasibility of reclaiming TNT from waste munitions by supercritical CO2 fluid extraction. It was found interestingly that the melting point of TNT can be lowered in supercritical CO2 fluid. Therefore, the melting process of TNT was observed under different temperature and pressure conditions to determine the best operating conditions for stripping-down TNT from waste munitions. Afterwards, simulated warheads with weight loadings of 60 g, 500 g and 1 kg of TNT were prepared and stripping-down tests from the simulated warheads were carried out using supercritical CO2 fluid at temperatures lower than the normal melting point of TNT. The results showed that TNT could be completely removed from the simulated warheads and the optimum operating conditions were determined as 55 °C and 25 MPa. This study will contribute to the feasibility evaluation of stripping-down TNT-based high explosives.
Źródło:
Central European Journal of Energetic Materials; 2018, 15, 1; 191-205
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-5 z 5

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