Electro-mechanically controlled assembly of reconfigurable 3D mesostructures and electronic devices based on dielectric elastomer platforms

The manufacture of 3D mesostructures is receiving rapidly increasing attention, because of the fundamental significance and practical applications across wide-ranging areas. The recently developed approach of buckling-guided assembly allows deterministic formation of complex 3D mesostructures in a broad set of functional materials, with feature sizes spanning nanoscale to centimeter-scale. Previous studies mostly exploited mechanically controlled assembly platforms using elastomer substrates, which limits the capabilities to achieve on-demand local assembly, and to reshape assembled mesostructures into distinct 3D configurations. This work introduces a set of design concepts and assembly strategies to utilize dielectric elastomer actuators as powerful platforms for the electro-mechanically controlled 3D assembly. Capabilities of sequential, local loading with desired strain distributions allow access to precisely tailored 3D mesostructures that can be reshaped into distinct geometries, as demonstrated by experimental and theoretical studies of ∼30 examples. A reconfigurable inductive–capacitive radio-frequency circuit consisting of morphable 3D capacitors serves as an application example.     

滤波器在图像处理中的应用

对原图像进行线性变换,增加了对比度和亮度,图像效果有了一定的改善;又用非锐化滤波器对修正后的图像进行了处理,对图像的过度失真进行了补偿,并对图像噪声滤波.     

Simplified method of designing FIR filter with controllable center frequency

A novel simplified method is presented to design FIR filter with controllable center frequency. The properties of transfer curves for all-phase filters are illustrated under 3 windowing conditions. By combining single-window all-phase filter design steps and double phase-shift combination, a series of design formulas for point-pass filter, notch filter, band-pass filter and band-stop filter are derived, thus the design computation complexity is greatly reduced. Experiments prove that the center frequency of all the filters can be accurately specified at arbitrary position by adjusting frequency parameters m and λ.     

基于机载LiDAR数据的建筑屋顶点云提取方法

机载激光雷达技术已经成为快速获取城市建筑三维数字模型的有效手段,而建筑物屋顶点云提取则是建筑物三维数字模型重建的关键。为有效剔除植被和墙面点云,以及消除地形起伏对建筑点云提取精度的影响,提出一种层进式屋顶点云提取方法。首先对LiDAR点云进行滤波,在此基础上利用点云回波特性和点云法向量检测并删除非地面点中特征明显的植被点和建筑物墙面点,然后利用连通成分分析法对非地面点聚类得到初始建筑点,最后结合DTM并利用建筑物面积和高度信息分离得到建筑物屋顶点云。试验结果表明,本方法能有效地从机载点云数据中快速提取建筑屋顶点云,有效率可达85%以上。     

基于卡尔曼滤波的PS-InSAR地表形变预测方法

PS-InSAR是用于监测大范围地表形变的微波遥感技术,可提供精确地表形变信息,但该技术无法对形变趋势进行预测。现有形变预测方法只能预测少数监测点的形变,不适用于大面积预测。针对这些问题,提出一种基于卡尔曼滤波的PS-InSAR地表形变预测方法。结合PS-InSAR方法的技术流程,从理论上推导设计卡尔曼滤波器,通过真实的多时相SAR数据对该方法进行验证。实验结果表明,该算法可充分利用PS-InSAR形变监测信息,有效预测大面积观测区域的形变趋势。     

Made in China: the cultural logic of OEMs and the manufacture of low‐cost technology

Abstract

This paper investigates the conditions of the manufacture of low‐cost technology in China with the examples of ‘pirated’ VCD players, ‘no‐name’ DVD players, and Shenzhen’s development as a techno‐urban city. It emphasizes the significance of the cultural logic of original equipment manufacturers (OEMs) and argues that the various transformations and deflections that are derived from ubiquitous OEM experiences have gone beyond the original model of an authorized OEM, experiences that are to some extent embodied in the transgression of brand name and patent hegemonies, which are mainly controlled by high technology companies. OEMs have been associated with China’s current imperative and uninhibited development of low‐cost technology capitalism. ‘Made in China’ signifies the production of any product, legal or illegal, for transnational high technology giants or domestic technology manufacturers. Learning to ‘become an OEM’ in China has partly resulted in excessive technological mimesis that may be part of an unauthorized, underground economy that is based on low‐cost technology. Based on the Shenzhen experience, part of this study will show industrial production‐oriented OEM cultures in which illegal operations and counterfeit trade are incorporated, even in city projects that are shared by municipal governments and Chinese technological companies, and undergo spatial restructuring in the development of the economy, consumerism, and urbanism.     

相位谱拟合车载自组网中功率增益优化方法

车载自组网WSN无线传感网络的接收/发射功率的无偏均衡设计,可以提高网络节点寿命,保证系统的稳定性,提高车载自组网的通信能力和网络连接率。传统方法采用的固定步长加权的滤波设计算法进行功率均衡设计,导致车载自组网的相邻节点功率均衡偏差,提出一种基于无偏均衡和相位谱拟合的车载自组网中功率增益优化算法,进行无偏均衡的车载自组网中网络连接率优化设计,确定节点一跳范围内的邻居节点,实现功率谱的估计,在功率均衡设计中,进行可变步长滤波设计,反映了信道幅值、时间和频率之间关系,对相位谱做最小二乘拟合求斜率,实现WSN可变步长滤波接收/发射功率无偏均衡算法改进。研究结果表明,该算法实现了接收/发射功率的无偏均衡,网传输距离提高,具有较大的功率增益,网络连接率较传统方法提高,展示了优越的应用性能。     

河南咨议局始末

清末新政之际,各省咨议局应运而生。河南咨议局在抚署官员的筹办和各地绅民的配合下,也走上了历史的舞台。在1909年到1911年短短两年中,经过前期的设立筹办处,选举咨议局议员,到正式开会,讨论各方议案。中间又发起了大规模的国会请愿运动,最后随着清朝的灭亡而消散。作为近代河南的民主尝试,这一小步的作用不能小看。     

基于光电二极管的动脉血压信号无损监测技术

用红外发光二极管和光电二极管组成的光耦合指套,放置在人身体的指尖部位,通过检测人体末梢组织在动脉舒张和收缩时对红外光的吸收度变化率,来检测人体动脉血压信号的异常.红外发射二极管的驱动采用PWM信号调制的恒流驱动,光电二极管接收穿透人体后的红外光并转换成微弱的电信号,再经过前置放大、倒相、压控二阶低通滤波、陷波电路、A/D转换等处理后,MCU从采集的数据中提取有关动脉血压信号的特征值,实现血压信号异常的无损连续监测.     

一种基于Kalman滤波和能量原理的实时损伤识别方法(英文)

目的:建立一种损伤识别方法,能够实时地监测多自由度复杂结构中构件的损伤情况。方法:1.用能量原理对结构刚度进行解构,建立结构单元刚度和节点响应之间的关系;2.用Kalman滤波原理分析结构刚度的预测值和测量值,迅速对结构的刚度进行识别(图6–9);3.对每一步计算进行耗时监测,确保算法的实时性(图10)。结论:1.该方法能够较准确地得到结构的刚度信息,同时得出损伤单元的损伤位置和损伤量;并且收敛速度快,计算量小,具有很强的实时性和抗噪能力;2.对于本文的桁架结构,所有杆件刚度均能在0.4 s内收敛,平均每一荷载步计算时间约为0.0012 s,小于采样周期1/256 s,说明该方法可以迅速、准确地对结构进行实时的监测。