一种基于无线射频通讯的共享雨伞系统

目前,以资源优化可利用和绿色出行为理念的共享经济蓬勃发展,基于此,本发明针对用户遇到突发性降雨天气时对雨伞临时需求,本文设计并实现了一款共享雨伞。本设计发明设计一类伞上装有电子标签的雨伞及雨伞借还系统,使用射频识别技术读取电子标签,使用Java技术编写微信小程序,利用STM32单片机控制伞桩的内部运行,便捷用户突遇突发性天气时及时满足用户对伞的需求,还提高社会资源的利用率。     

基于Khatri-Rao积的三维前视声呐空间方位估计技术

为了提高3维前视声呐的方位分辨能力,同时避免2维(2D)方位估计(DOA)方法失效,该文提出1维(1D)空间角估计方法、基于Vernier法的垂直角估计方法和基于最小角定理的水平角方位估计方法.首先基于不同子阵构造互协方差矩阵避免2维方位估计模型失效,再利用Khatri-Rao积进行虚拟孔径扩展;将扩展后的阵列导向矢量和观测向量模型用于2维方位估计.与原阵列的导向矢量相比,虚拟阵元数量约增加1倍,阵列的孔径得到有效扩展.仿真实验表明,与单观测向量波束形成2维方位估计方法相比,所提方法在2维方位估计问题中具有更高的分辨能力,均方根误差更低;水池实验进一步验证了该文所提方法的工程实用性.     

超宽带雷达人体行为感知研究进展

超宽带 (UWB) 雷达人体行为感知主要研究如何利用人体目标电磁散射回波对位置、行为、意图等进行判别,是光学感知手段的有益补充,应对无光照、地物遮挡、非视距等情况下的应用场合。该文将超宽带雷达人体行为感知研究方法分成基于空间位置和基于微动特征两类技术。在介绍这类技术基本原理的基础上,对比分析了国内外代表性工作的能力现状。最后对超宽带雷达人体行为感知领域的后续重点研究方向进行了展望。     

Physical Violence Detection Based on Distributed Surveillance Cameras

Mobile Networks and Applications - In recent years, physical violence detection has become a research hotspot in the area of human activity recognition. With the improvement and full coverage of...     

Metal Micropatterning by Triboelectric Spark Discharge

Metal micropatterns play critical roles in flexible electronics. However, the lack of versatile strategies for micropatterning of diverse metal materials on various thin, flexible or stretchable substrates has limited the rapid development of flexible electronics. Here, a metal micropatterning method by triboelectric spark discharge under atmospheric environment is developed, where a triboelectric nanogenerator (TENG) is employed to precisely and safely control the voltage, current, and frequency of the spark discharges. Micropatterns of metal films like gold, silver, copper, aluminum and platinum are successfully fabricated on substrates of polyimide, polyethylene terephthalate, polyvinyl chloride, polydimethylsiloxane, paper or latex, even on ultrathin substrates (5 μm thick) without damage, where the feature sizes of metal patterns are controllable from 20 μm to 1 mm. Experimental insights into the triboelectric spark discharge behaviors and the pattern feature sizes control are discussed. A straightforward fabrication of metal patterns on the balloon surface or human skin through “handwriting” by a pencil as discharge electrode is realized. Besides metals, extended processibility of conductive materials like carbon nanotubes, graphene, MXene, graphite, carbon fibers, and conductive polymers are also demonstrated. This work proves the possibility of microfabrication by TENG, which is of simplicity and attractiveness for flexible electronics.     

空间边缘计算:需求、架构及关键技术

随着航天电子技术的迅猛发展,特别是商用货架器件(COTS)的广泛使用,星载计算处理能力获得大幅跃升。空间边缘计算将广域分散的星载计算资源通过星间链路临机自组织成一个空间分布、计算协同的云环境,实现资源相助、任务协同,可以有效摆脱对地面的依赖、提升服务响应速度。该文首先从空间边缘计算的应用需求出发,梳理了空间边缘计算的发展现状以及存在的问题与挑战;然后在此基础上总结分析,提出一种空间边缘计算架构,并从物理架构、功能架构、软件架构以及服务流程等多维角度进行了阐述;最后对涉及的关键技术进行了概述和分析,以期能够为后续的研究提供有价值的建议和参考。     

Improve the quality of charging services for rechargeable wireless sensor networks by deploying a mobile vehicle with multiple removable chargers

Wireless Networks - The increasing demand for real-time applications of Wireless Sensor Networks (WSNs) makes Quality of Service (QoS)-based charging scheduling models an interesting and hot...     

Crystal Structure, Electrical Transport, and Magnetic Properties of Niobium Monophosphide

Large single crystals of NbP have been prepared. A single-crystal X-ray diffraction study shows that it crystallizes in tetragonal symmetry with space group I4(1)md (No. 109) and lattice parameters a = 3.3324(2) ?, c = 11.3705(7) ?, and Z = 4. A full matrix least-squares refinement based on a unique data set of 285 reflections (I> 2sigma(I)) yielded R(F) = 0.017 and R(w)(F(2)) = 0.046 for nine variables. The unit cell consists of one unique Nb and one P, each in trigonal prismatic coordination with the other element. There are two short and four long bond distances of Nb-P. The Nb-Nb bond distances are significantly shorter than R(c) = 4.09 ?, the critical distance required for good Nb-Nb 4d orbital overlap for niobium metal-metal bonds. NbP shows metallic behavior with rho = 4.5 x 10(-)(5) Omega cm at room temperature. Magnetic susceptibility measurements on a collection of randomly oriented single crystals indicate very weak Pauli paramagnetism ( approximately 10(-)(5) emu/mol). A discussion of the structure as well as the physical properties of NbP compared with those of previous results are presented. The band structure of NbP based on the extended Hückel (tight-binding) calculations is presented along with an analysis that reveals that the valence band is built up from three center bonds localized within Nb(3) triangles.     

Parametric normalization for full-energy peak count rates obtained at different geometries

The Effective Interaction Depth (EID) law has been systematically studied and applied to parametric normalization for peak count rates obtained at different source-detector distances (S-D). The errors caused by EID normalization are less than 4% over the full range of S-D (from to several mm) for true coincidence-free -rays. Parametric corrections for the true coincidence (summing) effect are also established, based on simplified decay schemes and P/T ratio determinations. The total response of Ge detector for single-energy -rays (T) is clearly defined with scattering contributions from surroundings included. Errors from summing effect corrections are also less than 4%. The combined EID normalization and summing effect corrections give an error no greater than 5.7% for the worst situations (several mm S-D and cascade-crossover decay scheme), acceptable for most practical K₀ NAA.