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Fully polarimetric synthetic aperture radar (SAR) has been widely used in applications, such as ground parameter inversion and classification. However, to accurately decipher the information contained in the polarimetric characteristics of an illuminated scene, the cross talks in cross-polarimetric channels and imbalances among co-pol channels must be removed from the measured polarimetric responses. Therefore, it is important to improve the polarimetric SAR calibration technique to reduce the distortions between various channels and calibrate the polarimetric data. In this article, we propose an efficient polarimetric SAR calibration method that uses known calibration point targets to remove the uncertainties among observed polarized responses. We first construct a common scattering model of natural targets organized by matrix products. Next, we reorder the square matrices in vector form. Finally, we construct a set of analytical equations based on the relations between theoretical and measured scattering matrices and derive the full elements of the distortion matrix by solving these equations. This algorithm determines the calibration matrix from corner reflectors with known scattering matrices, and it is efficient and easy to understand. Finally, we validate the algorithm with airborne C-band polarimetric SAR data.

In this study, Carbon Nanotube (CNTs) cement-based composites were investigated by adding Graphite Oxide (GO) together under the early age. The content and the ratio of GO and CNTs would significantly affect the electrical conductivity and mechanical properties of GO/CNTs cement-based composites. It was observed that the GO/CNTs composites with lower content GO (0.01 wt.%) and CNTs (0.05wt.%) could reach the percolation theory. Meanwhile, the mechanical properties (flexural, compressive strength) of GO/CNTs composites could be increased remarkably. It was also described that linear dependence between electrical conductivity and the stress of GO/CNTs cement-based composites could be found.

According to the climatic characteristics, the paper investigates relation between waterproof and air permeability of inorganic insulated decorative panel. The paper believes there are two main problems in the waterproof of inorganic insulated decorative panel, one is the gap is a weak link for waterproof as some weather proofing silicone sealants have poor elastic modulus, the other is the failure of construction details causes partial waterproofing failure. The composite panel system is best supplied in a complete set by the system supplier, which is a main comprehensive solution to the waterproofing problem of the composite panel. Through analyzing software simulation and experimental construction, the paper puts forward suggestion that hot summer and cold winter areas should take practical technical measures, including the use of the protective layer with high water vapor flux density or the installation of exhaust plugs in the outer wall base, or setting water vapor escaping channel such as PVC exhaust plug in the glue seam, in the actual project.