日像仪干涉阵结构优化的加速压力算法

提出的加速压力算法是对Boone压力算法在解的质量和收敛速度两方面的改进,通过一次移动天线阵,可以完全消除阵元数目个uv采样点处的残差,使得每次迭代的uv分布修正量最大,从而不仅达到减小计算量的目的,而且使优化结果更加逼近理想模型.通过ALMA阵结构的优化与原有算法做了对比,验证了算法的有效性和高效性.最后,给出了中国国家天文台正在建设的日像仪干涉阵结构的仿真结果     

On simplified Hurwitz stability conditions for low-degree weighted diamond polynomials

In this paper, the results on the stability of a weighted diamond of polynomials which was studied by Kharitonov and Tempo (Systems Control Lett. 22 (1994)) are simplified for low-order polynomials. Specifically, for n=3 and 4, the number of polynomials required to check the stability is four and six, respectively, instead of eight. Further, diamond of polynomials which were studied by Barmish et al. (IEEE Trans. Automat. Control AC-37 (9) (1992)) are also investigated.     

The structure and properties of spider silk

Silks from the spider's orb-web are amongst the very best structural materials produced by nature: spiders can produce a large aerial filter from a minimal amount of material. By studying how the structure and properties of silks are matched to their mechanical function, we can increase our general understanding of structure-property relationships in fibrous polymers.