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Detachment Behavior of Gecko Toe in Functional Strategies for Bionic Toe

Journal of Bionic Engineering 2024年第2期21卷 707-717页

作者： Qingfei Han Wei Wang Huan Shen Xincheng Feng Haoran Zhang Qian li Yi Sun huapeng Wu Aihong Ji Lab of Locomotion Bioinspiration and Intelligent Robots College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and AstronauticsNanjing210016China Laboratory of Intelligent Machines School of Energy SystemsLappeenranta-Lahti University of Technology53850LappeenrantaFinland State Key Laboratory of Mechanics and Control for Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China

Geckos can efficiently navigate complex terrains due to their multi-level adhesive system that is present on their toes.The setae are responsible for the gecko’s extraordinary adhesion and have garnered wide attention from the scientific community.The majority of the reported works in the literature that have dealt with the peeling models mainly focus on the gecko hierarchical adhesive system,with limited attention given to investigating the influence of gecko toe structure on the detachment.Along these lines,to gain a deeper understanding of the rapid and effortless detachment abilities of gecko toes,the peeling behavior of gecko toes on vertical surfaces was primarily investigated in this work.More specifically,the detachment time of a single toe on a smooth acrylic plate was measured to be 0.41±0.21 s.Moreover,it was observed that the toe assumed a"U"-shaped structure upon complete detachment.Additionally,Finite Element Analysis(FEA)models for three different types of gecko toes were developed to simulate both the displacement-peel and the moment-peel modes.Increasing the segmentation of the adhesive layer led to a gradual decrease in the resultant force,as well as the normal and tangential components.Lastly,a gecko-inspired toe model was constructed and powered by Shape Memory Alloy(SMA).A systematic comparison between the vertical drag separation and the outward flip separation was also conducted.From our analysis,it was clearly demonstrated that outward peel separation significantly necessitated the reduction of the peeling force,thus confirming the advantageous nature of the outward motion in gecko toe detachment.Our data not only contribute to a deeper understanding of the gecko detachment behavior but also offer valuable insights for the advancement of the wall-climbing robot feet.

关键词： Gecko toes Detachment behavior Finite element analysis Gecko-inspired toe

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Highly efficient nonuniform finite difference method for three-dimensional electrically stimulated liquid crystal photonic devices

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Photonics Research 2024年第4期12卷 865-875页

作者： ZHENGHAO GUO MENGJUN liU ZIJIA CHEN RUIZHI YANG PEIYUN li HAIXIA DA DONG YUAN GUOFU ZHOU liNGliNG SHUI huapeng YE Guangdong Provincial Key Laboratory of Optical Information Materials and Technology&Institute of Electronic Paper Displays South China Academy of Advanced OptoelectronicsSouth China Normal UniversityGuangzhou 510006China SCNU-TUE Joint Lab of Device Integrated Responsive Materials(DIRM) National Center for International Research on Green OptoelectronicsSouth China Normal UniversityGuangzhou 510006China Guangdong Provincial Key Laboratory of Nanophotonic Functional Materials and Devices School of Information and Optoelectronic Science and EngineeringSouth China Normal UniversityGuangzhou 510006China Joint Laboratory of Optofluidic Technology and Systems National Center for International Research on Green OptoelectronicsSouth China Academy of Advanced OptoelectronicsSouth China Normal UniversityGuangzhou 510006China College of Electronic and Optical Engineering&College of Microelectronics Nanjing University of Posts and TelecommunicationsNanjing 210046China Key Laboratory of Radio Frequency and Micro-Nano Electronics of Jiangsu Province Nanjing 210023China

liquid crystal(LC)photonic devices have attracted intensive attention in recent decades,due to the merits of tunability,cost-effectiveness,and high efficiency.However,the precise and efficient simulation of large-scale three-dimensional electrically stimulated LC photonic devices remains challenging and resource consuming.Here we report a straightforward nonuniform finite difference method(NFDM)for efficiently simulating largescale LC photonic devices by employing a spatially nonuniform mesh grid.

关键词： nonuniform crystal finite

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Temporal sequence Object-based CNN(TS-OCNN) for crop classification from fine resolution remote sensing image time-series

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The Crop Journal 2022年第5期10卷 1507-1516页

作者： huapeng li Yajun Tian Ce Zhang Shuqing Zhang Peter MAtkinson Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130012JilinChina Lancaster Environment Centre Lancaster UniversityLancaster LA14YQUK Faculty of Science and Technology Lancaster UniversityLancaster LA14YRUK

Accurate crop distribution mapping is required for crop yield prediction and field management. Due to rapid progress in remote sensing technology, fine spatial resolution(FSR) remotely sensed imagery now offers great opportunities for mapping crop types in great detail. However, within-class variance can hamper attempts to discriminate crop classes at fine resolutions. Multi-temporal FSR remotely sensed imagery provides a means of increasing crop classification from FSR imagery, although current methods do not exploit the available information fully. In this research, a novel Temporal Sequence Object-based Convolutional Neural Network(TS-OCNN) was proposed to classify agricultural crop type from FSR image time-series. An object-based CNN(OCNN) model was adopted in the TS-OCNN to classify images at the object level(i.e., segmented objects or crop parcels), thus, maintaining the precise boundary information of crop parcels. The combination of image time-series was first utilized as the input to the OCNN model to produce an ‘original’ or baseline classification. Then the single-date images were fed automatically into the deep learning model scene-by-scene in order of image acquisition date to increase successively the crop classification accuracy. By doing so, the joint information in the FSR multi-temporal observations and the unique individual information from the single-date images were exploited comprehensively for crop classification. The effectiveness of the proposed approach was investigated using multitemporal SAR and optical imagery, respectively, over two heterogeneous agricultural areas. The experimental results demonstrated that the newly proposed TS-OCNN approach consistently increased crop classification accuracy, and achieved the greatest accuracies(82.68% and 87.40%) in comparison with state-of-the-art benchmark methods, including the object-based CNN(OCNN)(81.63% and85.88%), object-based image analysis(OBIA)(78.21% and 84.83%), and standard pixel-wise CNN(79.18%and 82.90%). The proposed approach is

关键词： Convolutional neural network Multi-temporal imagery Object-based image analysis(OBIA) Crop classification Fine spatial resolution imagery

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基于深度学习的我国科技政策属性识别

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科研管理 2024年第2期45卷 1-11页

作者：李牧南王良赖华鹏华南理工大学工商管理学院广东广州510641 广东省创新方法与决策管理系统重点实验室广东广州510641

当前基于深度学习算法的文本分析更多聚焦于微博、评论和新闻头条为代表的舆情监测和情感分析等短文本信息处理,而针对各类政策文本、论文和专利全文的属性识别和长文本分类等相关研究较少,存在一定拓展空间。与传统的机器学习模型相比... 详细信息

当前基于深度学习算法的文本分析更多聚焦于微博、评论和新闻头条为代表的舆情监测和情感分析等短文本信息处理,而针对各类政策文本、论文和专利全文的属性识别和长文本分类等相关研究较少,存在一定拓展空间。与传统的机器学习模型相比,深度学习在自然语言处理和文本特征提取方面具有显著优势,其可通过预训练语言模型降低特征工程的人工干预,从而在政策属性和政策工具识别等领域具有较好的应用前景。本文针对我国科技政策属性(引导型、强制型和鼓励型)的自动识别问题,导入当前流行的几种深度学习模型进行了对比分析。与此同时,本文还针对政策文本的取词长度、数据增强和文本信息量估算等关联计算问题也进行了理论解析,从而进一步丰富了深度学习模型在科学计量,尤其是科技政策文本分析领域的应用。理论和实证分析结果显示,经过基于EDA(Easy Data Augmentation)方法的文本数据增强之后,当前几种代表性的深度学习模型在面向较为抽象的科技政策属性识别问题上均显著提升了处理能力,其中EDA+Bi-LSTM-Attention的识别准确率超过88%,其他参与实验的深度学习模型(TextCNN、Bi-LSTM、RCNN、CapsNet和FastText等)在文本增强之后的平均识别率也超过了80%;但是,文本取词长度从500词增加到2000词对中文科技政策属性识别的效果提升不显著。本文的研究对于科技政策属性自动识别、中文长文本分类和政策工具识别等科技管理相关量化分析具有一定的启示意义和参考价值。

关键词：深度学习科技政策属性识别数据增强文本分类

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低成本隧道双向天线的研究

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移动信息 2024年第6期46卷 4-6页

作者：黎华鹏中国电子科技集团公司第七研究所广州510310

文中提出了一种低成本隧道双向天线,其中4个集合线组成两个背对的共用反射板的对数周期天线,沿反射板天线辐射臂与辐射臂间距减小,集合线末端接同轴线缆,通过PCB功分板与同轴线缆对天线进行等幅同相馈电,实现了在低成本方案下的前后双... 详细信息

文中提出了一种低成本隧道双向天线,其中4个集合线组成两个背对的共用反射板的对数周期天线,沿反射板天线辐射臂与辐射臂间距减小,集合线末端接同轴线缆,通过PCB功分板与同轴线缆对天线进行等幅同相馈电,实现了在低成本方案下的前后双向馈电。该天线具有低驻波、高增益、波束集中、方向图稳定、制作方便、成本低廉等优点,具有较高的应用价值。

关键词：高增益低成本双向馈电

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Group screening for ultra-high-dimensional feature under linear model

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Statistical Theory and Related Fields 2020年第1期4卷 43-54页

作者： Yong Niu Riquan Zhang Jicai liu huapeng li School of Statistics East China Normal UniversityShanghaiPeople’s Republic of China Department of Mathematics and Physics Hefei UniversityHefeiPeople’s Republic of China Department of Mathematics Shanghai Normal UniversityShanghaiPeople’s Republic of China

Ultra-high-dimensional data with grouping structures arise naturally in many contemporary statistical problems,such as gene-wide association studies and the multi-factor analysis-of-variance(ANOVA).To address this issue,we proposed a group screening method to do variables selection on groups of variables in linear models.This group screening method is based on a working independence,and sure screening property is also established for our approach.To enhance the finite sample performance,a data-driven thresholding and a two-stage iterative procedure are developed.To the best of our knowledge,screening for grouped variables rarely appeared in the literature,and this method can be regarded as an important and non-trivial extension of screening for individual variables.An extensive simulation study and a real data analysis demonstrate its finite sample performance.

关键词： Ultra-high-dimensional group screening linear model sure screening property

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A Scale Sequence Object-based Convolutional Neural Network(SS-OCNN)for crop classification from fine spatial resolution remotely sensed imagery

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International Journal of Digital Earth 2021年第11期14卷 1528-1546页

作者： huapeng li Ce Zhang Yong Zhang Shuqing Zhang Xiaohui Ding Peter M.Atkinson Chinese Academy of Sciences Northeast Institute of Geography and AgroecologyChangchunPeople’s Republic of China School of Electrical and Information Engineering Changchun Guanghua UniversityChangchunPeople’s Republic of China Lancaster Environment Centre Lancaster UniversityLancasterUK Guangzhou Institute of Geography GuangzhouPeople’s Republic of China

The highly dynamic nature of agro-ecosystems in space and time usually leads to high intra-class variance and low inter-class separability in the fine spatial resolution(FSR)remotely sensed imagery.This makes traditional classifiers essentially relying on spectral information for crop mapping from FSR imagery an extremely challenging task.To mine effectively the rich spectral and spatial information in FSR imagery,this paper proposed a Scale Sequence Object-based Convolutional Neural Network(SS-OCNN)that classifies images at the object level by taking segmented objects(crop parcels)as basic units of analysis,thus,ensuring that the boundaries between crop parcels are delineated precisely.These segmented objects were subsequently classified using a CNN model integrated with an automatically generated scale sequence of input patch sizes.This scale sequence can fuse effectively the features learned at different scales by transforming progressively the information extracted at small scales to larger scales.The effectiveness of the SS-OCNN was investigated using two heterogeneous agricultural areas with FSR SAR and optical imagery,respectively.Experimental results revealed that the SS-OCNN consistently achieved the most accurate classification results.The SS-OCNN,thus,provides a new paradigm for crop classification over heterogeneous areas using FSR imagery,and has a wide application prospect.

关键词： CNNs multi-scale deep learning object-based mapping crop classification image classification

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数字社会治理的探索与实践——基于西藏新冠疫情防控视角

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中国公共卫生管理 2024年第1期40卷 33-37页

作者：朱华鹏李晓洁西藏大学经济与管理学院西藏拉萨850000

面向数字社会实践和急需化解的重大疫情问题开展深度研究是实践之需,以此为切入口推动数字社会治理研究,尤其是在治理工具、空间和发展方向上的深入探索更是题中应有之义。西藏2022年新冠疫情治理中的多元任务场域和数字场景、虚实互构... 详细信息

面向数字社会实践和急需化解的重大疫情问题开展深度研究是实践之需,以此为切入口推动数字社会治理研究,尤其是在治理工具、空间和发展方向上的深入探索更是题中应有之义。西藏2022年新冠疫情治理中的多元任务场域和数字场景、虚实互构的数字空间、信缘群体和数字产业等,均彰显出数字技术在市域社会空间场域中从工具到空间渗透的递进治理效应,证实了数字技术对疫情治理的正效应。但针对数字技术在疫情防控的应急状态中暴露出的治理限度问题,应持续放大数字治理的含金量,推动数字治理不断向纵深发展的同时回归社会现实。

关键词：数字社会数字治理疫情防控数字抗疫

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小型化多频基站天线的设计

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移动信息 2024年第3期46卷 15-17,20页

作者：黎华鹏朱志明中国电子科技集团公司第七研究所广州510310

文中设计了一种工作频段为698~960MHz的新型低频辐射单元,该辐射单元上方可嵌套4个工作频段为1700~2700MHz的高频辐射单元,实现一列低频两列高频的多频天线,底板宽度只有280mm,与常规三频天线的宽度380mm相比,宽度减小约26%,减小了天线... 详细信息

文中设计了一种工作频段为698~960MHz的新型低频辐射单元,该辐射单元上方可嵌套4个工作频段为1700~2700MHz的高频辐射单元,实现一列低频两列高频的多频天线,底板宽度只有280mm,与常规三频天线的宽度380mm相比,宽度减小约26%,减小了天线尺寸,实现了天线的小型化设计。仿真结果表明,该方案在698~960MHz及1700~2700MHz的水平面方向上,能满足常规基站天线的需求。

关键词：基站天线多频嵌套移动通信

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基于光纤端面集成的液晶光束整形器件

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液晶与显示 2024年第5期39卷 672-682页

作者：张永瑛李佩芸郭政昊袁冬叶华朋周国富华南师范大学华南先进光电子研究院广东广州510640

光纤集成器件因其尺寸小、功能高度集成化等优点,近年来受到越来越多的关注。当前光纤集成器件通常由介质型或金属型微结构组成,其制备加工通常依赖于高精度的微纳加工技术,面临着成本高和工艺复杂等挑战。另外,静态、固定几何结构的光... 详细信息

光纤集成器件因其尺寸小、功能高度集成化等优点,近年来受到越来越多的关注。当前光纤集成器件通常由介质型或金属型微结构组成,其制备加工通常依赖于高精度的微纳加工技术,面临着成本高和工艺复杂等挑战。另外,静态、固定几何结构的光纤光学器件功能不可调,也在极大程度上限制了其应用范围。本文设计并验证了一种基于光纤端面集成的液晶光束整形器件。通过对单模光纤端面加工平行锚定和垂直锚定的液晶聚合物液滴,获得了可见光波段的光束整形器件。基于Q-张量模型和Rayleigh-Sommerfeld衍射理论,实现了具有特殊液晶指向矢排布的液晶聚合物液滴的模拟仿真。通过实验验证了不同锚定条件下液晶聚合物液滴的光学性能,实验结果与仿真结果基本吻合,证明了该液晶器件的光束整形能力。这种液晶器件为光纤光学器件的微型化与集成化提供了一种成本较低、高效便捷的全新途径。

关键词：光束整形光纤端面液晶聚合物液滴液晶指向矢集成化器件

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