An yttrium aluminum garnet (YAG) crystal fiber with a thulium-doped end tip was specially grown by means of the laser heated pedestal growth approach and designed to be incorporated in a fiber-optic ...temperature probe. The fluorescence decay characteristics of the crystal fiber, including the temperature dependence of both the fluorescence lifetime and intensity, were comprehensively investigated. Experimental results indicated that the crystal fiber showed a monotonic relationship between the fluorescence lifetime and temperature with an average lifetime sensitivity of 3 mu s degree C over a wide temperature range, taking measurement from room temperature to 1200 degree C. Good stability (up to 1400 degree C) was observed with high repeatability of the fluorescence lifetime during the annealing process carried out on the fiber over this temperature range. The fiber was found to be an excellent candidate material to be used as a fluorescence decay-based fiber thermometer probe and the results are presented on its performance.
Due to complex subsurface situation, echo signals surveyed with Ground Penetration Radar (GPR) often contain a lot of clutters, including direct-coupling wave, random noises and multiples. Existence ...of these clutters submerges measured feature signals of rock structures with GPR, so suppression of them is often essential conduct for rock feature extraction. For extracting rockmass structure features from surveyed GPR data signals, sparse representation (SR) of the signals is an invaluable scheme with a small number of elementary signals from over-complete dictionary. In processing GPR signal data for extraction of rock structure and fracture features, this paper investigates sole Curvelet transform or matching pursuit (MP) for directcoupling wave and clutter suppression and feature extraction, and analyzes their limitations. By modeling ground penetrating radar signals with sparse decomposition, the method can achieve better results. Experimental results with simulation as well as real field data show that the proposed sparse decomposition achieves efficient signal representation and yields discriminative features for geological interpretation.
The impedance characteristic of folded-waveguide (FW) slow-wave structure (SWS) is studied in this paper. The impedance parameters are determined by the high-frequency parameters, especially the ...digital electromagnetic field data from a high-frequency structure simulator. After the analysis of the gap impedance of different radii and different angles, the formula of interaction impedance is presented. Finally, the coupling impedance is studied and compared with the interaction impedance. The method can be applied to other complex SWSs that lack of effective analytical methods.
THz wave propagation properties in a magnetized thermal plasma is researched in this paper. In the plasma, the electron density as well as the collision frequency are supposed to be Gaussian ...function. The non-uniform plasma is treated as a number of subslabs in which the electron density remains constant. The temperature of plasma, as well as the magnetic field, is considered. Particularly, twice reflection in each subslab is introduced. The absorbed and transmitted power ratios are simulated.
A novel honeycomb reflectarray constructed from hexagonal-ring unit is proposed for the generation of convergent orbital angular momentum (OAM) waves. The proposed hexagonal-ring unit is with very ...succinct structure and a wide operating band, which binds further with the hexagonal lattice and obtain a full-polarization response of the incident wave.
In cloud computing, variability becomes a crucial ability of process-based cloud applications. Existing solutions either focused on modeling variability in the architectural model or tried to support ...dynamic variability management in implementation. An integrated approach that can inherit the virtues from both categories is expected. The paper aims to fill the gap by proposing a model-driven variability-based service composition approach. We propose VxUML to model the variability in the architecture model. Then, we define a set of model transformation rules to convert VxUML into VxBPEL (an extension to standard BPEL supporting variability at the implementation level). Finally, we implement a prototype tool, and present a case study to demonstrate the feasibility of our approach.
An yttrium aluminum garnet (YAG) crystal fiber with a thulium-doped end tip was specially grown by means of the laser heated pedestal growth approach and designed to be incorporated in a fiber-optic ...temperature probe. The fluorescence decay characteristics of the crystal fiber, including the temperature dependence of both the fluorescence lifetime and intensity, were comprehensively investigated. Experimental results indicated that the crystal fiber showed a monotonic relationship between the fluorescence lifetime and temperature with an average lifetime sensitivity of 3 mus deg C over a wide temperature range, taking measurement from room temperature to 1200 deg C. Good stability (up to 1400 deg C) was observed with high repeatability of the fluorescence lifetime during the annealing process carried out on the fiber over this temperature range. The fiber was found to be an excellent candidate material to be used as a fluorescence decay-based fiber thermometer probe and the results are presented on its performance.
An electronically reconfigurable unit cell with 1-bit phase resolution (0°/180°) is presented for programable transmit-array lens (TAL) in C-band. The I-bit phase resolution is obtained by using two ...PIN diodes integrated in the transmitting layer of the unit cell. The simulated results verify that the proposed unit can achieve good 1-bit phase tuning, with minimum insertion loss of 0.2 dB and 2-dB transmission bandwidth of about 10%.
A dual-polarized transmit-array lens (TAL) is presented for the generation of dual-mode convergent orbital angular momentum (OAM) beams in C-band. The proposed TAL consists of dual-polarized ...metamaterial unit cells, which are composed of four stacked patches coupled by cross aperture, to complete the phase correction for both polarizations and stimulate the dual-mode convergent OAM beams. The simulated results verify the effectiveness of the proposed design.
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