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All Passive Realization of Lossy Coupling Matrices Using Resistive Decomposition Technique
摘要： A complex coupling matrix has been extensively used in lossy filters and negative group delay devices. For the realization, conventional technique decomposes the complex coupling matrix into lossy resonators and complex inverters. Since the complex inverter does not follow the passivity in some cases, the resultant realization may be globally passive but locally active. This paper proposes a new decomposition technique to ensure the passivity everywhere. It decomposes the complex coupling matrix into a resistive connection matrix and a conventional real coupling matrix, which are both passively realizable. This technique provides a passive realization of the complex coupling matrix. Furthermore, a loss equalization technique is also proposed, to further achieve a uniform quality factor (Q) distribution among all the lossy resonators. Several illustrative examples and an experimental validation are finally provided.
关键词： Lossy filter,resistive connection,quality factor,decomposition,complex coupling matrix,complex inverter
更新于2025-09-23 15:22:29
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Visible light photocatalytic dye decomposition behaviour of solid state reaction grown Zn <sub/>2</sub> TiO <sub/>4</sub> nanoparticles
摘要： In this investigation, visible photocatalytic dye decomposition is carried out with compound semiconductor nanoparticles of zinc orthotitanate (Zn2TiO4). These nanoparticles were grown by the solid state reaction method and characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, diffuse reflectance spectroscopy, photoluminescence study, and Brunauer–Emmett–Teller (BET) study. The BET surface area of the Zn2TiO4 nanoparticles was found to be 8.78 m2/g. The photocatalytic activity is carried out by using a 500 W halogen light source having a spectrum in the range of 450 to 860 nm and the reaction kinetics was found to be the pseudo first order. The reaction rate constant was found to be 0.069 min?1. Discussion is given on the possible mechanism of the observed visible photocatalytic dye decomposition activity. The cost of the material used is very low, so it could be very useful for visible photocatalytic dye decomposition.
关键词： visible photocatalysis,zinc orthotitanate,solid state reaction,dye decomposition,nanoparticles
更新于2025-09-23 15:22:29
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[IEEE 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Tangier (2017.12.4-2017.12.7)] 2017 International Renewable and Sustainable Energy Conference (IRSEC) - Solar Panels Frames Quality Assessment
摘要： Maintaining solar plant maximum energy production requires a regular inspection of solar panels. Images stitching technique of captured videos is usually used to form panoramic image view of the solar plant. Analyze of those images help supervisors to detect cracks, dust accumulation, …. Often captured videos are done using moveable devices, such as vehicle robots and drones. Usually, motion and shaking of devices provoke some blur captured frames which affect drastically the stitching process. In this paper, we study, experiment, and compare a set of techniques allowing to detect and discard blurred frames. As result, the algorithm based on Fourier Transform allows an efficient (i.e. accuracy of about 98%) and rapid treatment which can be easily integrated into online stitching process.
关键词： Blur estimation,Magnitude Fourier transform,DCT analysis,Image edges,SVD decomposition,Frame quality,Frames stitching
更新于2025-09-23 15:22:29
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Retraction： Wetting Behavior of Single Crystal TiO<sub>2</sub> by Liquid Iron
摘要： The wetting behavior of TiO2 by liquid iron was investigated by using the sessile drop method. A partial melting behavior was found to appear at the temperature below the melting point of the pure iron. Also a solid solution TiOx–FeO phase was observed between the pure iron and TiO2 substrate. The formation of this reaction layer is due to the reaction among the pure iron, TiO2 substrate and the oxygen gas. The main source of the oxygen gas for reaction is from the TiO2 substrate decomposition and a low partial pressure of oxygen near the sample.
关键词： TiO2,wettability,partial pressure oxygen,decomposition
更新于2025-09-23 15:22:29
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The influence on sample preparation on spectral induced polarization of unconsolidated sediments
摘要： Spectral induced polarization (SIP) measurements in the laboratory are in many cases intended to provide representative and comparable results of complex electrical conductivity. This is not invariably the case when using unconsolidated sediments, as the sample preparation influences several SIP-relevant properties of the samples, including the pore geometry. The pore space is supposed to control the polarization effect and therefore a change in the pore space will change the measured parameters. We analysed the influence of the sample preparation on SIP measurements by testing various filling methods, each defined by a sequence of particular steps, with regard to the reproducibility of the spectra. The measurements were performed on three different sample materials. Variations of the spectra due to different filling methods were obtained, indicating the importance of considering the sample preparation. Methods that improved the reproducibility compared to loose packing of the samples were found, but the most suitable packing procedure depended on the material properties. The mean relaxation times and normalized chargeabilities were obtained from a Debye decomposition. Although unidentified processes caused scattering of the measured parameters, a relation of the IP-parameters to the porosities was present. A decrease of the porosity reduced both the relaxation times and the normalized chargeabilities.
关键词： Debye decomposition,sample preparation,unconsolidated sediments,reproducibility,spectral induced polarization,porosity
更新于2025-09-23 15:22:29
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CdO Nanoparticles by Thermal Decomposition of a Cadmium- Hexamethylenetetramine Complex
摘要： CdO nanoparticles have been prepared by the thermal decomposition of a precursor complex. A simple and cost effective room temperature synthetic technique allows the preparation of the precursor complex from hexamethylenetetramine and cadmium nitrate in ethanol. The precursor, characterized by elemental analysis, mass spectrometry, Fourier transform infrared spectroscopy (FTIR), and thermal gravimetric analysis, had the composition [{Cd(HMTA)(NO3)2(H2O)2}n]. It was calcined at 500 oC for 2 h, and the cadmium oxide nanoparticles obtained was characterized by X-ray diffraction (XRD), scanning electron microscopy, high resolution transmission electron microscopy (HRTEM), Nitrogen adsorption and physisorption, and Selected Area Electron Diffraction (SAED). XRD shows that the CdO obtained is pure and crystalline. The particles obtained had a cubic morphology and are mesoporous.
关键词： thermal decomposition,hexamethylenetetramine,nanoparticles,cadmium oxide
更新于2025-09-23 15:22:29
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Material Decomposition in X-ray Spectral CT Using Multiple Constraints in Image Domain
摘要： X-ray spectral CT appears as a new promising imaging modality for the quantitative measurement of materials in an object, compared to conventional energy-integrating CT or dual energy CT. We consider material decomposition in spectral CT as an overcomplete ill-conditioned inverse problem. To solve the problem, we make full use of multi-dimensional nature and high correlation of multi-energy data and spatially neighboring pixels in spectral CT. Meanwhile, we also exploit the fact that material mass density has limited value. The material decomposition is then achieved by using bounded mass density, local joint sparsity and structural low-rank (DSR) in image domain. The results on numerical phantom demonstrate that the proposed DSR method leads to more accurate decomposition than usual pseudo-inverse method with singular value decomposition (SVD) and current popular sparse regularization method with (cid:2)1-norm constraint.
关键词： Sparse representation,X-ray spectral CT,Material decomposition,Low-rank representation
更新于2025-09-23 15:22:29
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A Domain Decomposition Finite Element Method for Modeling Electromagnetic Scattering from Rough Sea Surfaces with Emphasis on Near-Forward Scattering
摘要： A high fidelity full-wave simulator is presented to perform numerical experiments for rough sea scattering problem by considering different polarizations, frequencies, grazing angles, wind speeds and sea surface spectra. The simulator is based on a novel Finite Element Domain Decomposition (FEDD) method for solving the problem of two dimensional electromagnetic scattering over one-dimensional sea surface. This non-iterative method partitions the computational domain into a number of overlapping subdomains and solves each domain individually by employing the Locally-Conformal Perfectly Matched Layer (LC-PML) at the truncation boundaries. LC-PML has a unique feature such that it can be applied to irregular domains on the contrary to standard PML methods, and hence inspired the birth of FEDD. The FEDD method is used at each Monte Carlo realization corresponding to a sample from random rough surfaces, and decreases the computational load especially for electrically-large problems. The accuracy and computational efficiency of the method is investigated through several simulations. Using the FEDD method, the statistical behavior of the bistatic Radar Cross Section (RCS) is obtained for both horizontal and vertical polarizations. A special emphasis is given to forward-scattered RCS and the mean reflection coefficient for sea surface especially at low grazing angles, and it is shown that the simulator produces results in agreement with the Ament and Miller-Brown approximations, and experimental data, proving the reliability of the simulation approach. The results are also compared with the standard finite element method and method of moments. Rough sea surfaces are created by using both Pierson-Moskowitz and Elfouhaily spectra.
关键词： Locally-Conformal Perfectly Matched Layer (PML),forward scattering,sea surface,Domain decomposition,Monte Carlo,rough surface scattering,Finite Element Method (FEM),propagation,reflection coefficient,bistatic Radar Cross Section (RCS),multipath
更新于2025-09-23 15:21:21
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Assessment of Fringe Pattern Decomposition with a Cross-Correlation Index for Phase Retrieval in Fringe Projection 3D Measurements
摘要： Phase retrieval from single frame projection fringe patterns, a fundamental and challenging problem in fringe projection measurement, attracts wide attention and various new methods have emerged to address this challenge. Many phase retrieval methods are based on the decomposition of fringe patterns into a background part and a fringe part, and then the phase is obtained from the decomposed fringe part. However, the decomposition results are subject to the selection of model parameters, which is usually performed manually by trial and error due to the lack of decomposition assessment rules under a no ground truth data situation. In this paper, we propose a cross-correlation index to assess the decomposition and phase retrieval results without the need of ground truth data. The feasibility of the proposed metric is verified by simulated and real fringe patterns with the well-known Fourier transform method and recently proposed Shearlet transform method. This work contributes to the automatic phase retrieval and three-dimensional (3D) measurement with less human intervention, and can be potentially employed in other fields such as phase retrieval in digital holography.
关键词： parameter selection,cross-correlation,Fourier transform,phase retrieval,Shearlet transform,fringe pattern decomposition
更新于2025-09-23 15:21:21
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[IEEE IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Valencia, Spain (2018.7.22-2018.7.27)] IGARSS 2018 - 2018 IEEE International Geoscience and Remote Sensing Symposium - Forest Height Estimation Using Adaptive Decomposition Method of Polinsar Data
摘要： In this paper, we present an approach to retrieve forest height using an adaptive scattering model decomposition technique with PolInSAR data. This method combines the adaptive scattering model decomposition technique and the coherence amplitude method. This procedure enables the retrieval not only of the vegetation parameters but also of the magnitude associated with each mechanism. To test the performance of the proposed method ESAR PolInSAR L band data of Oberpfaffenhofen, in Germany is used to show the accuracy of the forest height estimation.
关键词： interferometry,Model-based decomposition,polarimetry,forest height estimation
更新于2025-09-23 15:21:21