2,299 research outputs found
Electromagnetic transmission of an oblique waveguide array
No full textTransverse magnetic (TM) and transverse electric (TE) wave transmissions of an oblique parallel-plate waveguide array is studied. The scattered wave is represented in terms of continuous and discrete modes based on the Fourier transform and series, respectively. The tangential field continuities at the boundary are enforced to obtain simultaneous equations for the discrete modal coefficients. Residue calculus is utilized to transform the radiation field and reflection coefficient into numerically efficient forms. Numerical computations are performed to illustrate the behavior of wave radiation and reception by an oblique waveguide array
Electrochemical properties of carbon nanotube/silicon composites for anode of Li-ion battery
No full textUndetactable levels of genotoxicity of SiO2 nanoparticles in in vitro and in vivo tests [Erratum]
No full textKwon JY, Kim HL, Lee JY, et al. Int J Nanomedicine. 2014;9(Suppl 2):173–181.The title of the paper “Undetactable levels of genotoxicity of SiO2 nanoparticles in in vitro and in vivo tests” should read “Undetectable levels of genotoxicity of SiO2 nanoparticles in in vitro and in vivo tests”.Read the original articl
Acoustic scattering from two junctions in a rectangular waveguide
No full textAcoustic scattering from two junctions in a rectangular waveguide is studied. Fourier transform and mode matching are used to represent the scattered wave and the simultaneous equations for the modal coefficients are formulated. The residue calculus is utilized to obtain a solution to the simultaneous equations in fast-converging series. Numerical evaluation shows the behaviors of transmission and reflection in terms of the junction geometry and operating frequency. (C) 1998 Acoustical Society of America. [S0001-4966(98)00802-9]
STRUCTURAL AND OPTICAL-PROPERTIES OF HYDROGENATED AMORPHOUS-SILICON CARBIDE DEPOSITED BY GLOW-DISCHARGE FROM C3H8-SIH4-H2 MIXTURE
No full textFilms of hydrogenated amorphous silicon carbide (a-SiC:H) have been prepared by a glow discharge decomposition from ps mixtures Of C3H8-SiH4-H2 and CH4-SiH4-H2, in order to examine the effect of hydrocarbon gases on the structural and optical properties of these films. To study the influence of hydrogen on those properties of the propane-based films, the properties of the films deposited at different substrate temperatures (T(s)) are systematically investigated using infrared (IR) and ultraviolet-visible absorption spectroscopies. By observing the change of intensities of IR absorption peaks with substrate temperature, the hydrogen bonding responsible for the absorption peaks could be assigned more accurately. When T(s) is increased up to 300-degrees-C, intensities of CH3 and SiH2 groups are reduced, indicating the formation of a dense network structure. At the same carbon concentration in ps mixtures, propane allows more carbon and hydrogen atoms to be effectively incorporated into the film than methane. The IR spectra reveal that the structure of a propane-based film has the characteristics of that of two kinds of films, methane- and ethylene-based films. It is found that the chemical bonding nature of the hydrocarbon ps strongly affects the bonding structure and the composition of the films. From these results, it is proposed that the use of propane is suitable for the fabrication of high-quality a-SiC:H with a wide optical gap ( > 2.0 eV) and a deposition rate of approximately 2 angstrom/s
Nonisothermal crystallization behavior of SPS/APS blends
No full textThe nonisothermal crystallization behavior of syndiotactic polystyrene (SPS)/ atactic polystyrene (APS) blends was studied with differential scanning calorimetry to investigate the effects of APS on the crystallization behavior of SPS. Polarized optical microscopy and wide-angle X-ray diffractometry were also used to observe the morphology of the SPS crystalline structure. From a cyclic heating/cooling temperature program, we obtained found that APS retarded the crystallization (and recrystallization) of SPS and made the crystal less perfect, but the ultimate crystallinity of SPS did not change with the addition of APS. We also observed that APS was disposed in the interfibrillar region of SPS spherulites and did not change the crystalline form of SPS. This result will be helpful for improving SPS applications through blending with rubber-toughened APS. (C) 2000 John Wiley & Sons, Inc
Satellite selection scheme for reducing handover attempts in LEO satellite communication systems
No full textLow earth orbit (LEO) satellite communication systems perform frequent intersatellite handovers for both foxed and mobile users. This paper proposes a satellite selection scheme for new/handover call requests when two or more satellites can be seen simultaneously. Each satellite in this scheme has a non-uniform transmitter antenna gain according to its relative position inside the coverage area. The antenna gain is proportional to the residual distance in the satellite's direction of movement and it compensates for the difference in path losses between satellite links. The residual distance distribution of the selected satellite and the mean number of intersatellite handovers during a call connection are calculated and compared with the results based on conventional methods. The proposed scheme can reduce the intersatellite handover call attempt rate without increasing system load and terminal complexity. Furthermore, this scheme can be extended to reduce both intersatellite and interbeam handover call attempt rates in a multiple spot beam environment. Especially, the average number of intersatellite and interbeam handovers during a call can be significantly reduced by using a hybrid algorithm with the proposed non-uniform power transmission scheme. (C) 1998 John Wiley & Sons, Ltd
Noise parameter extraction of a GaAs MESFET with Monte-Carlo simulation
No full textAll of the noise parameters of a GaAs metal-semiconductor field-fffect transistor (MESFET) are extracted using 2-dimensional Monte-Carlo simulation for the first time. The general procedure for extracting the noise parameters is presented. The spectrums and correlations of the input-equivalent noise-voltage and noise-current sources are calculated. The y parameters of a GaAs MESFET are also extracted to obtain noise parameters and to analyze device characteristics for the first time
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