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Abstract-High-resolution wide-swath (HRWS) imaging with spaceborne synthetic aperture radar (SAR) can be achieved by using azimuth displacement phase center antenna (DPCA) technique. However, it will consequently leads to extremely high data rate on satellite downlink system. A novel sparse sampling scheme based on compressed sensing (CS) theory for azimuth DPCA SAR was proposed, by which only a small proportion of radar echoes are utilized for imaging to reduce data rate. The corresponding image formation algorithm for the proposed scheme was presented in the paper. The SAR echo signal of each channel can be reconstructed with high probability by using orthogonal matching pursuit (OMP) algorithm in Doppler frequency domain. The reconstructed echo signals of each channel are jointly processed by means of spectrum reconstructing filter for compensating Doppler spectrum aliasing resulting from non-uniform sampling in azimuth direction. The high quality SAR image can be obtained by using chirp scaling algorithm. The effectiveness of the proposed approach was validated by computer simulations using both point targets and distributed targets.

Experiments were carried out to investigate the deformation and energy absorbing characteristics and mechanisms of foamed aluminum (FA) with two different matrices. Some new results were obtained. It is found that, like other cellular solid materials, FA has a stress-strain curve with three distinct regions, i.e., the linear elasticity region, the plastic collapse region or brittle crushing region, and the densification region. The energy absorbing capacity of FA increases by increasing the relative density and the yielding strength. Brittle foam exhibits higher capacity than plastic foam with similar yielding strengths. FA reaches its peak value of energy absorbing efficiency at the strain of about 0.15 to 0.35, depending on the relative density. AlMg10 foam shows higher absorbing capacity and efficiency than Al foam.

In this paper, in order to examine the mechanisms of sonodynamic and photodynamic reactions, the chlorophyllin metal (Chl-M (M=Fe, Mg and Cu)) complexes were irradiated by ultrasound (US) and visible-light (VL), respectively, and the generation of reactive oxygen species (ROS) were detected by the method of Oxidation-Extraction Spectrometry (OES). That is, the 1,5-diphenyl carbazide (DPCI) is oxidized by the generated ROS into 1,5-diphenyl carbazone (DPCO), which can display a various visible absorption around 563 nm wavelength. Besides, some influence parameters on the generation of ROS were also reviewed. The results demonstrated an apparent synergistic effect of Chl-M and ultrasonic or visible-light irradiation for the generation of ROS. Moreover, the quantities of generated ROS increase with the increase of (ultrasonic or visible-light) irradiation time and Chl-M (M=Fe, Mg and Cu) concentration. Finally, several quenchers were used to determine the kind of the generated ROS. It is wished that this paper might offer some valuable references for the study on the sonodynamic therapy (SDT) and photodynamic therapy (PDT) mechanisms and the application of Chl-M in tumor treatment.