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Multiscale Structure engineering for High-Performance Pb-Free Piezoceramics

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Accounts of Materials Research 2022年第4期3卷 461-471页

作者： Xiang Lv Ting Zheng Chunlin Zhao Jie Yin Haijun wu Jiagang wu Department of Materials science Sichuan UniversityChengdu 610064China State Key Laboratory for Mechanical Behavior of Materials Xi’an Jiaotong UniversityXi’an 710049China

CONSPECTUS:The increasing world energy crisis drives humans to harvest the energy in nature as much as possible without heavily damaging the ***,most of the energy in nature cannot be used ***,pursuing technologies or matter that can directly interconvert different energies has been one of the most cutting-edge fields in science and *** a magic ability exists in true-life piezoelectric materials that generate charge when being given a force and vice versa,rendering them highly promising for energy harvesting and conversion because of the tremendous mechanical energy on the earth,such as tide ***,piezoelectric materials,represented by the lead zirconate titanate(Pb(Zr,Ti)O_(3),PZT)family,have been largely used in various traditional and burgeoning fields,such as electronic information,biomedical treatment,and wearable flexible electronic devices,and are one of the most important favorites in multidisciplinary ***,Pb is highly *** by environmental protection and concern for human health,Pb-free piezoceramics are rapidly being developed to hopefully replace Pb-based *** particular,the renewal of Restriction of the use of certain Hazardous Substances(e.g.,RoHS 2),issued by the European Union,declared that replacement of PZT“...may be scientif ically and technologically practical to a certain degree...”.Therefore,developing high-performance Pb-free piezoceramics has become more urgent than *** this context,some Pb-free piezoceramics,represented by potassium sodium niobate((K,Na)NbO_(3),KNN),barium titanate(BaTiO_(3),BT),bismuth barium titanate((Bi,Na)TiO_(3),BNT),and bismuth ferrite(BiFeO_(3),BFO),stand out because of their unique or similar ***,several key challenges,including an inferior overall performance compared to Pb-based counterparts and an unclear structure−property relationship from multiscale viewpoints,have severely hindered the development of Pb-free piezoceramics for

关键词： ceramics piezoelectric bismuth

FUZZY PRINCIPAL COMPONENT ANALYSIS AND ITS KERNEL-BASED MODEL

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Journal of Electronics(china) 2007年第6期24卷 772-775页

作者： wu Xiaohong Zhou jianjiang College of information science ＆ technology Nanjing University of Aeronautics and Astronautics Nanjing 210016 China College of Electrical ＆ information engineering Jiangsu University Zhenjiang 212013 China

Principal Component Analysis(PCA)is one of the most important feature extraction methods,and Kernel Principal Component Analysis(KPCA)is a nonlinear extension of PCA based on kernel *** real world,each input data may not be fully assigned to one class and it may partially belong to other *** on the theory of fuzzy sets,this paper presents Fuzzy Principal Component Analysis(FPCA)and its nonlinear extension model,i.e.,Kernel-based Fuzzy Principal Component Analysis(KFPCA).The experimental results indicate that the proposed algorithms have good performances.

关键词： Principal Component Analysis (PCA) Kernel methods Fuzzy PCA (FPCA) Kernel PCA (KPCA)

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模态联合空域估计的毫米波雷达呼吸心率检测

陕西科技大学学报 2024年第3期42卷 188-196页

作者：廖涛万相奎贡文新武明虎王滨辉湖北工业大学湖北省电网智能控制与装备工程技术研究中心湖北武汉430068

在毫米波雷达检测人体呼吸率和心率过程中,周围环境存在的静态杂波使得雷达极难分辨人体胸腔运动信息,从而影响了呼吸信号和心跳信号的分离.同时,由于呼吸信号在高频带的谐波分量与心跳信号所处低频带部分的频率相近,很难分离.为解决上... 详细信息

在毫米波雷达检测人体呼吸率和心率过程中,周围环境存在的静态杂波使得雷达极难分辨人体胸腔运动信息,从而影响了呼吸信号和心跳信号的分离.同时,由于呼吸信号在高频带的谐波分量与心跳信号所处低频带部分的频率相近,很难分离.为解决上述问题,提出了一种模态联合空域估计的检测方法,主要采用单轮集成经验模态分解(SEEMD)算法将胸腔相位信号分解为各模态分量,以消除静态杂波对呼吸心跳信号的影响,再采用多重信号分类(MUSIC)算法将心跳模态分量信号由时域转换到空域中估计其频率,以消除呼吸谐波的影响.实验结果表明,本方法检测下的呼吸率准确率为95.76%,心率准确率为98.76%.与传统算法相比,本文所提方法下的呼吸率和心率估计更为准确.

关键词：毫米波雷达单轮集成经验模态分解多重信号分类

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基于空间灰度重心推进的线结构光中心提取

电子测量技术 2024年第2期47卷 44-50页

作者：卜民众吴国新黄金鹏左云波刘秀丽北京信息科技大学现代测控技术教育部重点实验室北京100192 北京信息科技大学机电工程学院北京100192

利用线结构光对工件进行三维测量时,快速、准确提取激光光条中心是测量系统的关键技术之一。提出一种基于空间灰度重心推进的激光中心提取方法。该方法基于激光条纹空间灰度重心向前推进,结合八邻域判定法进行光条空间区域的选取,接着... 详细信息

利用线结构光对工件进行三维测量时,快速、准确提取激光光条中心是测量系统的关键技术之一。提出一种基于空间灰度重心推进的激光中心提取方法。该方法基于激光条纹空间灰度重心向前推进,结合八邻域判定法进行光条空间区域的选取,接着对选取的区域进行新的空间灰度重心坐标提取;在完成整幅图像提取后,采取3σ准则剔除异常中心点,最终获得激光中心坐标信息。实验结果表明,所提算法对不同类型条纹的适用性强,提取效果稳定。提取中心均方根误差为0.492pixel,相较于提取精度最优的Steger改进算法提升了9.8%,提取速度提高了5倍;相较于处理速度最优的内部推进算法,在保持提取速度基础上,提取精度提升了24.1%。同时,所提算法极大增强了对欠曝光光条图像的处理能力,有效降低了环境对线结构光测量的限制。

关键词：测量线结构光空间灰度重心 3σ准则

岗位有害物质控制效率用于局部通风设施防护效果评估的探讨

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中国安全生产科学技术 2014年第4期10卷 193-196页

作者：陈建武中国安全生产科学研究院北京100029

工程防护是消除和控制职业病危害因素的重要方法,而职业病危害工程防护设施防护效果评估的首要任务是明确其评价指标与评估标准。针对局部通风设施防护效果评估,提出了岗位有害物质控制效率评价指标,并对比分析了职业接触限值、控制风... 详细信息

工程防护是消除和控制职业病危害因素的重要方法,而职业病危害工程防护设施防护效果评估的首要任务是明确其评价指标与评估标准。针对局部通风设施防护效果评估,提出了岗位有害物质控制效率评价指标,并对比分析了职业接触限值、控制风速、有害物质捕集效率和该指标的优缺点;提出了岗位有害物质控制效率的定义、检测方法和评估标准,对该指标用于局部通风设施防护效果评价存在的问题进行了讨论,并提出了下一步的研究方向。

关键词：控制效率防护效果职业病危害局部通风设施

Human movement monitoring and behavior recognition for intelligent sports using customizable and flexible triboelectric nanogenerator

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science china(Technological sciences) 2022年第4期65卷 826-836页

作者： YANG Yun HOU XiaoJuan GENG WenPing MU JiLiang ZHANG Le WANG XiangDong HE jian XIONG Ji Jun CHOU Xiujian science and technology on Electronic Test and Measurement Laboratory North University of ChinaTaiyuan 030051China Department of Mining engineering Luliang UniversityLvliang 033000China Physical Education Institute Jimei UniversityXiamen 361021China

Effective collection,recognition,and analysis of sports information is the key to intelligent sports,which can help athletes to improve their skills and formulate scientific training plans and competition *** present,wearable electronic devices used for movement monitoring still have some limitations,such as high cost and energy consumption,incompatibility of suitable flexibility and personalized spatial structure,dissatisfactory data analysis methods,*** this work,a novel three-dimensionalprinted thermoplastic polyurethane is introduced as the elastic shell and friction layer,and it endows the proposed customizable and flexible triboelectric nanogenerator(CF-TENG)with personalized spatial structure and robust correlation to external *** practical application,it exhibits highly sensitive responses to the joint-bending motion of the finger,wrist,or ***,a pressure-sensing insole and smart ski pole based on CF-TENG are manufactured to build a comprehensive sports monitoring system to transmit the athletes’motion information from feet and hands through the plantar pressure distribution and ski pole *** recognize the movement status,the self-developed automatic peak recognition algorithm(P-Find)and machine learning algorithm(subspace K-Nearest Neighbors)were introduced to accurately distinguish the four typical motion behaviors and three primary sub-techniques of cross-country skiing,with accuracy rates of 98.2%and 100%.This work provides a novel strategy to promote the personalized applications of TENGs in intelligent sports.

关键词： triboelectric nanogenerator flexible movement monitoring behavior recognition intelligent sports

基于纳米碳填料可拉伸导电聚合物复合材料的制备

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化学进展 2021年第3期33卷 417-425页

作者：张天永吴畏朱剑李彬姜爽天津大学化工学院天津300072 南开大学材料科学与工程学院国家新材料研究院天津300350

碳系材料具有导电性强、稳定性好、价格低廉等优点,被广泛用于制备可拉伸导电复合材料,并且在可拉伸、可穿戴电子设备等领域有巨大的应用潜力,引起了研究者的密切关注。本文介绍了碳系材料的种类,主要有炭黑、碳纳米管和石墨烯等;总结了... 详细信息

碳系材料具有导电性强、稳定性好、价格低廉等优点,被广泛用于制备可拉伸导电复合材料,并且在可拉伸、可穿戴电子设备等领域有巨大的应用潜力,引起了研究者的密切关注。本文介绍了碳系材料的种类,主要有炭黑、碳纳米管和石墨烯等;总结了3种纳米复合材料的主要制备工艺:原位聚合法、熔融共混法和溶液混合法,并介绍了传统印刷技术和新型打印技术。分析了复合材料的导电机理,介绍了渗流阈值理论;并重点探讨了其在可拉伸传感器和可拉伸能量储存设备领域的应用。针对基于纳米碳填料制备的可拉伸导电聚合物复合材料指出目前研究的不足之处:导电填料分散性差、导电网络不稳定和无法大规模生产等,并提出了多种解决方案。对基于纳米碳填料制备的可拉伸导电聚合物复合材料在微型化、可拉伸、可穿戴电子设备领域的应用前景作出了展望。

关键词：碳材料聚合物复合材料可拉伸电子设备渗流阈值

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基于特征条件扩散模型的雷达回波外推算法

科学技术与工程 2024年第22期24卷 9498-9509页

作者：吴其亮王兴苗子书叶威良王思成向磊南京信息工程大学人工智能学院南京210044 包头市气象局包头014030 南京信息工程大学计算机学院南京210044

随着外推时效的延长,回波强度愈发衰减,且对于强回波的预报性能迅速下降。这是当前雷达外推结果不准确的两个典型特征。为改善上述问题,提出了一种通过雷达回波帧驱动的扩散雷达外推算法(diffusion radar echo extrapolation,DiffREE)... 详细信息

随着外推时效的延长,回波强度愈发衰减,且对于强回波的预报性能迅速下降。这是当前雷达外推结果不准确的两个典型特征。为改善上述问题,提出了一种通过雷达回波帧驱动的扩散雷达外推算法(diffusion radar echo extrapolation,DiffREE)。该算法利用条件编码模块将过去雷达回波帧的空间信息和时效信息深度融合,通过Transformer编码器自动提取回波的时空特征,并作为条件扩散模型的条件,驱动扩散模型重建当前雷达回波帧。实验结果表明,该方法可以生成高精度、高质量的雷达预报帧,较最好的基线算法在CSI、ETS、HSS和POD上分别提升42.2%、51.1%、49.8%和39.5%。

关键词：深度学习短时预报雷达回波外推扩散模型条件编码

Non-spreading Bessel spatiotemporal optical vortices

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science Bulletin 2022年第2期67卷 133-140,M0003页

作者： Qian Cao jian Chen Keyin Lu Chenhao Wan Andy Chong Qiwen Zhan school of Optical-Electrical and Computer engineering University of Shanghai for Science and TechnologyShanghai 200093China school of Optical and Electronic information Huazhong University of Science and TechnologyWuhan 430074China Department of Physics University of DaytonDayton OH 45469USA Department of Electro-Optics and Photonics University of DaytonDayton OH 45469USA

Non-spreading nature of Bessel spatiotemporal wavepackets is theoretically and experimentally investigated and orders of magnitude improvement in the spatiotemporal spreading has been *** spatiotemporal confinement provided by the Bessel spatiotemporal wavepacket is further exploited to transport transverse orbital angular momentum through embedding spatiotemporal optical vortex into the Bessel spatiotemporal wavepacket, constructing a new type of wavepacket: Bessel spatiotemporal optical vortex. Both numerical and experimental results demonstrate that spatiotemporal vortex structure can be well maintained and confined through much longer propagation. High order spatiotemporal optical vortices can also be better confined in the spatiotemporal domain and prevented from further breaking up, overcoming a potential major obstacle for future applications of spatiotemporal vortex.

关键词： Optical vortices Bessel spatiotemporal wavepacket Orbital angular momentum Spatiotemporal vortex