科创中国

Many attentions for structural synthesis are paid to planar linkages and parallel mechanisms, while design novel pyramid deployable truss structure(PDTS) of satellite SAR mainly depends on experience of designer. To design novel configuration of PDTS, a two-step topology structure synthesis and analysis approach is proposed. Firstly, a conceptual configuration of PDTS is synthesized. Weighted graph and weighted adjacency matrix are established to realize topological description for PDTS. Graph properties are then summarized to distinguish differentia between PDTS and other type structures. According to graph properties, a procedure for synthesis conceptual configuration of PDTS is presented. Secondly, join relationship of components in a PDTS is analyzed. Kinematic chain and corresponding incidence/adjacency matrix are employed to analyze join relationship of PDTS. Properties and simplified rules of kinematic chain are extracted to construct kinematic chain. A procedure for construction kinematic chain of PDTS is then established. Finally, with this two-step approach all 11 rectangular pyramid deployable structures whose folded state is planar are discovered and their kinematic chains are constructed. Based on synthesis results, a novel deployable support structure for satellite SAR is designed. The proposed research can be applied to obtain some novel PDTSs, which is of great importance to design some novel deployable support structures for satellite SAR antenna.

由于超分辨率图像的重建是典型的不适定问题,因此常引入正则化约束来稳定求解.在正则化方法的基础上,提出了一种针对SAR图像不同区域自适应处理的正则SAR图像超分辨重建新算法.该算法根据图像的邻域一致性测度构造自适应平滑约束项,并定义自适应的p L范数对此项进行度量.同时,构造基于1L范数的梯度逼近范数项,将其加入正则化的重建过程中,进一步提高SAR图像的重建质量.实验结果表明,该算法不仅具有良好的稳健性,而且在较好地重建SAR图像细节信息的同时,有效地抑制了斑点噪声,明显改善了重建SAR图像的质量.

SAR图像的空间域压缩多采用矢量量化的方法进行.通常的块自适应矢量量化性能好但计算量较大,而残差矢量量化计算量小却在性能上有劣势.基于此,提出了一种新的基于块自适应残差矢量量化的SAR图像压缩算法.根据SAR幅值图像具有近似瑞利分布的特点对图像先进行基于瑞利分布的块自适应矢量量化,然后利用残差图像数据具有近似高斯分布的特点进行二次块自适应矢量量化.并且在残差矢量量化中进行了按照均方误差排序选择性压缩的改进,在压缩比不变的前提下有效提高了压缩系统性能.多幅图像的实验结果表明,相对传统的块自适应矢量量化和残差矢量量化,该算法在达到较高压缩性能和较低计算资源占用量以及较少存储空间占用上获得了有效的改进.

本实验提供了一种新的PVA/P=AAS/EDTA高吸水性树脂及其制备方法.采用聚乙烯醇(Poly vinyl alcohol.PVA)、聚丙烯酸钠(Polyacrylate sodium,PAAS)和乙二胺四乙酸(Ethylene diamine tetraacetic acid,EDTA),将由这些材料组成的水溶液经电子束辐射交联合成共聚物凝胶,经浸洗液溶胀和洗涤,萃冻和冷冻干燥后处理,制备出耐盐性高吸水性树脂.采用正交设计原理选出最佳配比,用不同配比的洗涤液进行后处理,研究洗涤液对树脂吸液性能的影响.测试树脂的各项性能,与国内外著名产品进行比较.结果表明,本实验制备出的高吸水性树脂具有优良的吸液速率和离心保液量,去离子水吸液倍率((821.05±1.61)g·g^-1)和生理盐水吸液倍率((72.57±3.01)g·g^-1)则非常显著地优于国内外著名高吸水性树脂产品(P〈0.01).