字节全加器及其在无线电测控系统中的应用

对全加器概念进行了推广，并在此基础上给出了使用字节全加器网络的无线电抗干扰算法。通过在实际的无线电测控系统中的应用，结果表明该算法具有良好的无线电抗干扰效果。     

基于PLC的三维调整机同步控制系统设计与实现

针对三维调整机难以实现多台同步工作，设计了基于PLC的同步控制方案。在同步控制系统方案中，采用西门子PLC通过工业无线以太网进行同步控制，由各维度油缸的位移传感器来保证同步控制的精确性。经实验，证实了此系统的精度满足设计要求，实现了同步控制的效果。     

Porous shape memory polymers: Design and applications

Porous shape memory polymers (SMPs) exhibit geometric and volumetric shape change when actuated by an external stimulus and can be fabricated as foams, scaffolds, meshes, and other polymeric substrates that possess porous three-dimensional macrostructures. These materials have applications in multiple industries such as textiles, biomedical devices, tissue engineering, and aerospace. This review article examines recent developments in porous SMPs, with a focus on fabrication methods, methods of characterization, modes of actuation, and applications. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1300–1318     

Single molecule study of DNA collision with elliptical nanoposts conveyed by hydrodynamics

Periodic arrays of micro‐ or nanopillars constitute solid‐state matrices with excellent properties for DNA size separation. Nanofabrication technologies offer many solutions to tailor the geometry of obstacle arrays, yet most studies have been conducted with cylinders arranged in hexagonal lattices. In this report, we investigate the dynamics of single DNA collision with elliptical nanoposts using hydrodynamic actuation. Our data show that the asymmetry of the obstacles has minor effect on unhooking dynamics, and thus confirm recent predictions obtained by Brownian dynamics simulations. In addition, we show that the disengagement dynamics are correctly predicted by models of electrophoresis, and propose that this consistency is associated to the confinement in slit‐like channels. We finally conclude that elliptical posts are expected to marginally improve the performances of separation devices.     

Actuating Shape Memory Polymer for Thermoresponsive Soft Robotic Gripper and Programmable Materials

For soft robotics and programmable metamaterials, novel approaches are required enabling the design of highly integrated thermoresponsive actuating systems. In the concept presented here, the necessary functional component was obtained by polymer syntheses. First, poly(1,10-decylene adipate) diol (PDA) with a number average molecular weight M_n of 3290 g·mol⁻¹ was synthesized from 1,10-decanediol and adipic acid. Afterward, the PDA was brought to reaction with 4,4′-diphenylmethane diisocyanate and 1,4-butanediol. The resulting polyester urethane (PEU) was processed to the filament, and samples were additively manufactured by fused-filament fabrication. After thermomechanical treatment, the PEU reliably actuated under stress-free conditions by expanding on cooling and shrinking on heating with a maximum thermoreversible strain of 16.1%. Actuation stabilized at 12.2%, as verified in a measurement comprising 100 heating-cooling cycles. By adding an actuator element to a gripper system, a hen’s egg could be picked up, safely transported and deposited. Finally, one actuator element each was built into two types of unit cells for programmable materials, thus enabling the design of temperature-dependent behavior. The approaches are expected to open up new opportunities, e.g., in the fields of soft robotics and shape morphing.     

基于质心迭代估计的无线传感器网络节点定位算法

针对无线传感器网络非测距定位方法的应用,提出了基于质心迭代估计的节点定位算法.该算法首先计算当前连通信标节点所围成的平面质心的坐标及其与未知节点间的接收信号强度,然后用计算所得质心节点替代距离未知节点最远的连通信标节点,缩小连通信标节点所围成的平面,并通过多次迭代的方法提高节点定位精度.仿真实验结果表明,该算法的各项指标均为良好,适用于无线传感器网络的节点定位.     

A realization of digital wireless transmission for MRI signals based on 802.11b

In this paper, a digital wireless transmission system based on 802.11b standard for magnetic resonance imaging (MRI) application is designed and built for the first time to eliminate the interference aroused by coil array cables. The analysis shows that the wireless receiver has a very high sensitivity to detect MRI signals. The modulation technique of differential quadrature phase shift keyed (DQPSK) can be applied to MRI data transmission with rate of 2 Mbps and bandwidth of 2 MHz. The bench test verifies that this wireless link has a dynamic range over 86 dB supporting up to 3 T MRI system data transmission. The 2D spin echo imaging of phantom is performed and the SNR of the image obtained by the wireless transmission can be comparable with that got by the coaxial cables.     

Electrical actuation of dielectric droplets by negative liquid dielectrophoresis

This paper presents an electrical actuation scheme of dielectric droplet by negative liquid dielectrophoresis. A general model of lumped parameter electromechanics for evaluating the electromechanical force acting on the droplets is established. The model reveals the influence of actuation voltage, device geometry, and dielectric parameter on the actuation force for both conductive and dielectric medium. Using this model, we compare the actuation forces for four liquid combinations in the parallel-plate geometry and predict the low voltage actuation of dielectric droplets by negative dielectrophoresis. Parallel experimental results demonstrate such electric actuation of dielectric droplets, including droplet transport, splitting, merging, and dispending. All these dielectric droplet manipulations are achieved at voltages < 100 V_rms. The frequency dependence of droplet actuation velocity in aqueous solution is discussed and the existence of surfactant molecules is believed to play an important role by realigning with the AC electric field. Finally, we present coplanar manipulation of oil and water droplets and formation of oil-in-water emulsion droplet by applying the same low voltage.     

基于ARM和nRF905组网的智能家居系统设计

针对家居中电器种类和数目繁多且分散于各室造成控制不便,提出了一种利用nRF905射频模块实现无线通信的智能家居控制系统。系统对射频数据传输协议进行了设计,给出了室内多个微控制器的组网方案。用户通过手机短信或万能遥控器把对家电的控制信号发送至基于ARM平台搭建的主控中心,再由主控中心发送至若干个通信节点或智能插座,万能遥控器通过射频信号实现对家电的近距离遥控,手机通过GSM通信实现对家电的远程遥控。通信节点基于STC89C52RC单片机设计,能够实现对多种红外家电的控制并具备安防报警功能,智能插座则用于控制非遥控家电。实验表明,该系统可使网络中各节点、插座得到有效的控制,数据传输稳定、功能丰富、可扩展性强,具备较高的应用价值。     

WSANs中基于蜂巢结构的移动容错恢复算法

旨在研究无线传感器与执行器网络(WSANs)中节点失效情况下恢复执行器(actor)节点服务的算法. 首先说明了WSANs中的实时覆盖模型, 证明WSANs覆盖恢复问题是NP难问题, 给出了近似求解方案. 在此基础上, 提出了一种基于六边形蜂巢结构的移动容错算法HMFR用于恢复失效actor节点, HMFR 算法在限制网络初始部署的条件下拥有很好的性能. 通过实验与现有的恢复算法进行比较, 发现HMFR算法在actor覆盖sensor节点数和移动距离方面有更好的性能.