Orientation angle compensation has been incorporated into model-based decomposition to cure the overestimation of volume scattering contribution, by rotating the coherency matrix to minimize the cross-polarization ter...
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ISBN:
(纸本)9781849196031
Orientation angle compensation has been incorporated into model-based decomposition to cure the overestimation of volume scattering contribution, by rotating the coherency matrix to minimize the cross-polarization term. However, this processing cannot always guarantee to rotate the double- and odd-bounce scattering components back to zero orientation angle cases and with zero cross-polarization power. Therefore, built-up patches with large orientation angles may still suffer from the scattering mechanism ambiguity. In this paper, general double- and odd-bounce scattering models are proposed to fit for the cross-polarization and off-diagonal terms, by separating their independent orientation angles. The general decomposition framework is proposed and utilizes the complete information. The residual minimization criterion is used for model inversion. The optimal solutions are obtained using the nonlinear least square optimization technique. The manual interference and negative power issues are well avoided during the model inversion. Its efficiency and advantages are demonstrated and evaluated with airborne Xband Pi-SAR polarimetric SAR datasets. Comparison studies are also carried out. Further improved decomposition performance is achieved by the proposed method, especially in oriented built-up areas.
Organic light-emitting diodes (OLEDs) were fabricated on nanostructured aluminum doped zinc oxide (AZO). The nanostructured AZO was formed by selectively etching as-prepared AZO film. The nanostructured AZO serves not...
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Organic light-emitting diodes (OLEDs) were fabricated on nanostructured aluminum doped zinc oxide (AZO). The nanostructured AZO was formed by selectively etching as-prepared AZO film. The nanostructured AZO serves not only as low-cost indium-free anode but also as internal light extraction structure. OLEDs on it showed a 25.7% efficiency enhancement compared to the conventional ones.
The line integral of Radon-Wigner Transform (RWT) can transform the line in Wigner-Ville distribution into a point in the plane, which can be used to estimate the chirp rate and initial frequency. The calculation is c...
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This paper proposes a control strategy of PWM rectifier for four-quadrant cascade inverter. Firstly, through analysis of the impact of the output power fluctuation of H-bridge inverter on the stability of the DC bus v...
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This paper proposes a control strategy of PWM rectifier for four-quadrant cascade inverter. Firstly, through analysis of the impact of the output power fluctuation of H-bridge inverter on the stability of the DC bus voltage and PWM rectifier control, a self-adjusting notch filter is added to the voltage outer loop. To reduce the impact of the variation of the AC side parameter on the control system, a proportional resonant (PR) controller is implemented to the current inner loop. And then, digital realization of the PR controller and the notch filter with direct form structure based on delta operator are achieved and the design principles of the key parameters are given. Finally, the experimental verification of PWM rectifier and its control strategy has a good four-quadrant performance in steady-state and transient operation under the rectification and inversion.
Effective online power system transient stability analysis and critical cutset detection method has important significance for the safe and stable operation of interconnected power system. Aiming at the disadvantages ...
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Effective online power system transient stability analysis and critical cutset detection method has important significance for the safe and stable operation of interconnected power system. Aiming at the disadvantages of the PEBS(potential energy boundary) method based on branch potential energy, a high reliable method named Branch RIDGE method is proposed in this paper for power system transient stability analysis and critical cutset detection. Also, a simple stability index of branch and system and a method to detect the stability status and critical cutsets of power system based on BPR and branch stability index are proposed. This method is established on the dynamic response trajectories of power system network information. In the case of known parameters of network structure, the method only needs real-time data of bus voltage magnitude and phase angle to do online power transient stability analysis and critical cutset detection. Because the method doesn't make assumption of two group instability mode, this method can be used in multi-swing instability and multi-group instability mode. The simulation on New England 10 machines show the validation of the proposed method.
The plasma parameters of planar-type surface-wave plasmas （SWPs） are diagnosed based on the resonant excitation of surface plasmon polaritons （SPPs）. The plasma parameter distributions are obtained by changing the...
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The plasma parameters of planar-type surface-wave plasmas （SWPs） are diagnosed based on the resonant excitation of surface plasmon polaritons （SPPs）. The plasma parameter distributions are obtained by changing the discharge conditions of gas pressure and incident power. The measured experimental results show that the plasma near the heating layer is excited by surface waves of SPPs while the plasma located downstream originates from diffusion Moreover, the influence of high-frequency oscillations plays a significant role in producing the proposed SWPs with bi-Maxwellian electron energy distributions.
As the basic of a deeper investigation on the turbulent transport, the fluctuation property in the boundary of the newly-reconstructed Joint Texas Experimental Tokamak （J- TEXT） is studied experimentally using the r...
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As the basic of a deeper investigation on the turbulent transport, the fluctuation property in the boundary of the newly-reconstructed Joint Texas Experimental Tokamak （J- TEXT） is studied experimentally using the reciprocating Langmuir four-tip probe, which has been built and operated as the primary diagnostic tool in the boundary of J-TEXT tokamak. In this paper, spatial profiles of the plasma-edge parameters are obtained, such as electron temperature, plasma density, plasma potential, poloidal electric field and their fluctuations. The results indicate the existence of a Er ×BT shear layer at the vicinity of last closed flux surface （LCFS）, with the fluctuations suppressed in varying degrees. The turbulence-induced particle and energy fluxes can be calculated by the local plasma parameters above. Convection dominates the cross-field turbulent transport in boundary plasma. Electrostatic fluctuations properties are also studied in detail with the help of numerical analysis. Statistical analysis on density fluctuation shows that, the intermittency can affect the turbulence in the scrape-off layer （SOL）.
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