A Minimalist Single-Layer Metasurface for Arbitrary and Full Control of Vector Vortex Beams

Vector vortex beams (VVBs) possess ubiquitous applications from particle trapping to quantum information. Recently, the bulky optical devices for generating VVBs have been miniaturized by using metasurfaces. Nevertheless, it is quite challenging for the metasurface-generated VVBs to possess arbitrary polarization and phase distributions. More critical is that the VVBs' annular intensity profiles demonstrated hitherto are dependent on topological charges and are hence not perfect, posing difficulties in spatially shared co-propagation of multiple vortex beams. Here, a single-layer metasurface to address all those aforementioned challenges in one go is proposed, which consists of two identical crystal-silicon nanoblocks with varying positions and rotation angles (i.e., four geometric parameters throughout). Those four geometric parameters are found to be adequate for independent and arbitrary control of the amplitude, phase, and polarization of light. Perfect VVBs with arbitrary polarization and phase distributions are successfully generated, and the constant intensity profiles independent of their topological charges and polarization orders are demonstrated. The proposed strategy casts a distinct perception that a minimalist design of just one single-layer metasurface can empower such robust and versatile control of VVBs. That provides promising opportunities for generating more complex vortex field for advanced applications in structural light, optical micromanipulation, and data communication.     

理想弹塑性厚壁圆筒弹塑性应力场再研究

对理想弹塑性厚壁圆筒受内外均布压力问题重新进行了研究，指出了现行应力场解答中存在的问题及产生这些问题的根源，并进一步求出了该问题的准确解答。     

浅谈构建水利与经济社会和谐发展的双赢平台

指出人水和谐不仅是一种理念也是一种方法,要利用这种理念,从经济学、社会学、生态学和系统学等不同研究方向来研究可持续发展理论,并应在治水中坚持人与自然和谐相处的观念,反映出价值取向的变化,从而由“以人为中心”和人控制自然、统治自然的价值理念,转变为以人为本、全面、协调、可持续发展的理念,最终达到人与自然和谐发展、共同发展。     

运用模糊数学结合层次分析法评价房屋完损等级

根据现有房屋完损等级评价标准，提出运用模糊数学的多级评判方法分层次确定房屋完损等级的隶属度，结合层次分析法(AHP)确定各个评价层次对于上一评价层次的权重综合评价房屋完损等级，使评价结果更加科学、合理。最后，给出算例证明此方法在实际中是可行的。     

奇周期最佳几乎二进序列偶理论研究

提出了一种新的具有良好奇周期相关特性的最佳离散信号——奇周期最佳几乎二进序列偶。奇周期最佳几乎二进序列偶中2个序列中均有一个元素为 “0”元素,其他元素取值均为“＋1”或“－1”,并且其奇周期自相关函数为单值脉冲函数。同时研究了奇周期最佳几乎二进序列偶的变换性质和频谱特性,给出了一些组合允许条件。研究结果表明,奇周期最佳几乎二进序列偶扩大了奇周期最佳几乎二进序列的存在空间,且为奇周期最佳几乎二进序列偶中2个序列相同时的特殊情况。     

为推行清单计价模式建立完善的地方造价信息网

文章探讨了工程量清单计价模式下信息技术对工程量清单计价体系的影响,提出了建立完善的地方造价信息网的途径。     

申报制造许可的几项建议

根据制造许可规则与型式试验细则规定，以及当前部分制造企业尚存在差距，提出从设计、文件、自检等方面贯彻电梯相关标准与加强质量控制的建设，以利达到顺利申报制造许可的目的。     

Uncertain impulsive differential systems of fractional order: almost periodic solutions

In this paper, we investigate the existence and stability of almost periodic solutions of impulsive fractional-order differential systems with uncertain parameters. The impulses are realised at fixed moments of time. For the first time, we determine the impact of the uncertainties on the qualitative behaviour of such systems. The main criteria for the existence of almost periodic solutions are proved by employing the fractional Lyapunov method. The global perfect robust uniform-asymptotic stability of such solutions is also considered. We apply our results to uncertain impulsive neural network systems of fractional order.     

Conditional matching preclusion for the alternating group graphs and split-stars

The matching preclusion number of a graph is the minimum number of edges the deletion of which results in a graph that has neither perfect matchings nor almost-perfect matchings. For many interconnection networks, the optimal sets are precisely those induced by a single vertex. Recently, the conditional matching preclusion number of a graph was introduced to look for obstruction sets beyond those induced by a single vertex. It is defined to be the minimum number of edges the deletion of which results in a graph with no isolated vertices that has neither perfect matchings nor almost-perfect matchings. In this article, we find this number and classify all optimal sets for the alternating group graphs, one of the most popular interconnection networks, and their companion graphs, the split-stars. Moreover, some general results on the conditional matching preclusion problems are also presented.