期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
Broadband and wide-angle plane focal surface Luneburg lens
1
作者 李珏 周杨阳 陈焕阳 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期16-20,共5页
The energy crisis has aroused widespread concern, and the reform of energy structure is imminent. In the future,the energy structure will be dominated by the solar energy and other renewable energy sources. The solar ... The energy crisis has aroused widespread concern, and the reform of energy structure is imminent. In the future,the energy structure will be dominated by the solar energy and other renewable energy sources. The solar concentrating technology as a promising method has been widely studied for collecting solar energy. However, the previous solar concentrating technologies suffer from some drawbacks, such as low focusing efficiency and large concentrating size. The Luneburg lens with highly efficient aberration-free focusing provides a new route for solar/energy concentrator. In this work, we designed a plane focal surface Luneburg lens(PFSLL) by transformation optics(TO). The PFSLL provides a relatively high focusing efficiency and concentration ratio of collection of energy. At the same time, it circumvents the disadvantage of curve surface of the classical Luneburg lens in device integration. Based on the reciprocity of electromagnetic waves, the PFSLL can also be applied to the antenna field to achieve broadband wide-angle scanning and highly directional radiation. 展开更多
关键词 plane focal surface Luneburg lens(PFSLL) focusing efficiency concentration ratio of collection of energy
下载PDF
Spacelike Framed Curves with Lightlike Components and Singularities of Their Evolutes and Focal Surfaces in Minkowski 3-space
2
作者 Peng Cheng LI Dong He PEI Xin ZHAO 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2024年第6期1521-1532,共12页
In this paper,we define the evolute and focal surface of a spacelike framed curve with lightlike components in Minkowski 3-space.It is a generalization of the previous results of regular spacelike curves,since singula... In this paper,we define the evolute and focal surface of a spacelike framed curve with lightlike components in Minkowski 3-space.It is a generalization of the previous results of regular spacelike curves,since singularities are allowed in the original spacelike curves studied by spacelike framed curves with lightlike components.Meanwhile,we show a new geometric invariant to characterise singularities of the focal surface.Then,the classification theorem and recognition theorem for the singularities of the focal surface in generic are also given. 展开更多
关键词 Evolutes focal surfaces spacelike framed curves SINGULARITIES
原文传递
A Kind of Rectilinear Congruences in the Minkowski 3-Space
3
作者 侯中华 李丽 《Journal of Mathematical Research and Exposition》 CSCD 北大核心 2008年第4期911-918,共8页
We consider the rectilinear congruence T generated by the tangents to a one parameter family of geodesics on a space-like surface S1 in the Minkowski 3-space E13, having S1 as one of its focal surfaces. We prove that ... We consider the rectilinear congruence T generated by the tangents to a one parameter family of geodesics on a space-like surface S1 in the Minkowski 3-space E13, having S1 as one of its focal surfaces. We prove that the two families of torsal surfaces of T touch the second focal surface S2 along the net of orthogonal parametric curves if and only if S1 is developable. We also obtain the necessary and sufficient condition for the correspondence between the points of S1 and S2 at the same rays preserving the... 展开更多
关键词 the rectilinear congruence the focal surfaces the Minkowski space the space-like surface maximal surfaces.
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部