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Thin-Film Radiative Thermal Diode with Large Rectification

Physical Review Applied 2021年第1期16卷 014069-014069页

作者： Qizhang Li Haiyu He Qun Chen Bai Song Beijing Innovation Center for Engineering Science and Advanced Technology Peking University Beijing 100871 China Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Department of Engineering Mechanics Tsinghua University Beijing 100084 China Department of Energy and Resources Engineering Peking University Beijing 100871 China Department of Advanced Manufacturing and Robotics Peking University Beijing 100871 China

We propose a mechanism to substantially rectify radiative heat flow by having one side of the thermal diode offering a large contrast in the local density of electromagnetic states, while the opposite side serving as a narrow bandpass filter that limits the transport to a desired spectral range. To demonstrate, we realize such a scenario by matching thin films of metal-to-insulator transition materials and polar dielectrics in the near field. By leveraging the distinct scaling behaviors of the local density of states with film thickness for metals and insulators, we theoretically achieve rectification ratios over 140, a 10-fold improvement over the state of the art, with nanofilms of vanadium dioxide and cubic boron nitride in the parallel-plane geometry at experimentally feasible gap sizes (∼100 nm). Our rational design offers relative ease of fabrication, flexible choice of materials, and robustness against deviations from optimal film thicknesses. We expect this work to facilitate the application of thermal diodes in solid-state thermal circuits and energy-conversion devices.

关键词： Heat transfer Metal-insulator transition Near-field optics Phonons Photodiodes Thin films Electromagnetic wave theory Landauer formula

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Study on Multi-Scale Failure Mechanism and Damage Evolution Constitutive Relation of Poly(Phthalazine Ether Sulfone Ketone) in a Wide Temperature Range

SSRN

引用

SSRN 2023年

作者： Shen, Liangliang Zhou, Xin Zhu, Tianqi Xiao, Chenglong Zhao, Gang Jian, Xigao Xu, Jian Ren, Zhiying State Key Laboratory of Fine Chemicals Liaoning High Performance Polymer Engineering Research Center School of Chemical Engineering Dalian University of Technology Dalian116024 China Engineering Laboratory of Advanced Energy Materials Ningbo Institute of Material Technology and Engineering Chinese Academy of Science Ningbo315201 China Department of Mechanical Materials and Manufacturing Engineering University of Nottingham Ningbo China Ningbo315100 China School of Mechanical Engineering and Automation Fuzhou University Fuzhou350116 China School of Mechanical Engineering Zhejiang University of Technology Hangzhou310018 China

In this work, the multi-scale failure and damage constitutive relationship of PPESK are investigated via quasi-static tensile/bending tests and scanning electron microscopy characterization methods, and the cross-scale three-dimensional failure damage evolution constitutive model of PPESK within a broad temperature range is constructed for the first time. Based on the findings, the temperature boundary effect concept of PPESK is proposed as follows: the cumulative damage of pore initiation and craze expansion and cracking at the microscopic scale of PPESK are the essential factors of material failure and damage at various temperatures, which simultaneously presents a strong The temperature sensitivity is specifically manifested in the gradual evolution of quasi-brittleness and viscoelasticity in the temperature range of 295 K-472 K. In order to further develop the basic research tools of materials, the secondary compilation input of the PPESK material property is performed in the finite element software, and the construction work of the PPESK multi-scale failure damage constitutive relationship is carried out. The experimental data are finally combined with the simulated crack failure pattern and mechanical behavior of the material, and the mapping relationship with the constitutive model for further validity verification. © 2023, The Authors. All rights reserved.

关键词： Constitutive models

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Printability and properties of PSNZT piezoelectric ceramics fabricated by DLP additive manufacturing

引用

Ceramics International 2025年

作者： Yu, Mengyuan Fan, Guifen Li, Yingkang Ling, Xile Gong, Feng Liu, Gang Bai, Jiaming Li, Mantian Zhou, Peng Zhang, Dongyang Sun, Lining Hubei Key Laboratory of Plasma Chemistry and Advanced Materials School of Materials Science and Engineering Wuhan Institute of Technology Wuhan430205 China Institute of Intelligent Manufacturing Technology Shenzhen Polytechnic University Shenzhen518055 China MOE Huazhong University of Science and Technology Wuhan430074 China Department of Mechanical and Electronic Engineering College of Mechatronics and Control Engineering Shenzhen University Shenzhen518055 China Shenzhen Blueswin Industrial Co. Ltd Shenzhen518117 China Department of Mechanical and Energy Engineering Southern University of Science and Technology Shenzhen518055 China Institute of Critical Materials for Integrated Circuits Shenzhen Polytechnic University Shenzhen518055 China Robotics and Microsystems Center School of Mechanical and Electric Engineering Soochow University Suzhou215021 China

Achieving the synergy of low viscosity, high printing precision and enhanced curing ability for lead zirconate titanate (PZT) components is a critical issue in the field of digital light processing (DLP). Herein, the effect of calcination temperature on the morphology and grain size of PSNZT [(Pb0.92Sr0.08)(Zr0.533Ti0.443Nb0.024)O3]ceramic powder has been investigated, and a lowest viscosity, higher printing precision and enhanced curing ability of PSNZT ceramic slurry has been achieved, resulting in a high piezoelectric constant (d33 = 379pC/N) and a high dielectric constant (Εr = 1308@100 KHz) via DLP process combined with following sintering densification (1220 °C/3 h). © 2025 Elsevier Ltd and Techna Group S.r.l.

关键词： Piezoelectric ceramics

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Radiative Thermal Diode via Hyperbolic Metamaterials

引用

Physical Review Applied 2021年第6期16卷 064022-064022页

Hyperbolic metamaterials (HMMs) support propagating waves with arbitrarily large wavevectors over broad spectral ranges, and are uniquely valuable for engineering radiative thermal transport in the near field. Here, by employing a rational-design approach based on the electromagnetic local density of states, we demonstrate the ability of HMMs to substantially rectify radiative heat flow. Our idea is to establish a forward-biased scenario where the two HMM-based terminals of a thermal diode feature overlapped hyperbolic bands which result in a large heat current, and suppress the reverse heat flow by creating spectrally mismatched density of states as the temperature bias is flipped. As an example, we present a few high-performance thermal diodes by pairing HMMs made of polar dielectrics and metal-to-insulator transition materials in the form of periodic nanowire arrays, and considering three representative kinds of substrates. Upon optimization, we theoretically achieve a rectification ratio of 324 at a 100-nm gap, which remains greater than 148 for larger gap sizes up to 1 µm over a wide temperature range. The maximum rectification represents an almost 1000-fold increase compared with a bulk diode using the same materials, and is twice that of state-of-the-art designs. Our work highlights the potential of HMMs for rectifying radiative heat flow, and may find applications in advanced thermal-management and energy-conversion systems.

关键词： Dielectric properties Heat transfer Metal-insulator transition Transport phenomena Diodes Hyperbolic metamaterials Electromagnetic wave theory Landauer formula

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Near-field thermal transport between twisted bilayer graphene

arXiv

引用

arXiv 2021年

作者： Yang, Fuwei Song, Bai Center for Nano and Micro Mechanics Tsinghua University Beijing100084 China Department of Energy and Resources Engineering Peking University Beijing100871 China Department of Advanced Manufacturing and Robotics Peking University Beijing100871 China Beijing Innovation Center for Engineering Science and Advanced Technology Peking University Beijing100871 China

Active control of heat flow is of both fundamental and applied interest in thermal management and energy conversion. Here, we present a fluctuational electrodynamic study of thermal radiation between twisted bilayer graphene (TBLG), motivated by its unusual and highly tunable plasmonic properties. We show that near-field heat flow can vary by more than 10-fold over only a few degrees of twist, and identify special angles leading to heat flow extrema. These special angles are dictated by the Drude weight in the intraband optical conductivity of TBLG, and are roughly linear with the chemical potential. Further, we observe multiband thermal transport due to the increasing role of interband transitions as the twist angle decreases, in analogy to monolayer graphene in a magnetic field. Our findings are understood via the surface plasmons in TBLG, and highlight its potential for manipulating radiative heat flow. Copyright © 2021, The Authors. All rights reserved.

关键词： Heat transfer

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Femtosecond Laser Ablation Behavior of Sic/Sic Composites in Air and Water Environment

SSRN

引用

SSRN 2022年

作者： Wei, Jiayong Yuan, Songmei Zhang, Jiaqi Zhou, Ning Zhang, Wei Li, Jiebo An, Wenzhao Gao, Mengxuan Fu, Yanzhe R&D Center of High-efficient & Green CNC Machining Technology and Equipment School of Mechanical Engineering and Automation Beihang University Beijing100191 China National Key Laboratory of Science and Technology on Power Beam Processes AVIC Aeronautical Manufacturing Technology Research Institute Beijing100024 China Institute of Medical Photonics Beijing Advanced Innovation Center for Biomedical Engineering School of Biological Science and Medical Engineering Beihang University Beijing100191 China

SiC/SiC composites (SiC matrix with SiC fibers) play an important role in aerospace and energy fields because of their good resistance to high temperature, corrosion, oxidation and low density. In this paper, we have qualitatively and quantitatively analyzed the ablation behavior of femtosecond laser processed SiC/SiC composites in air and water environments using multiple characterization tools. The results showed that ablation in air was characterized as thermochemical corrosion dominance, while in water expressed as thermomechanical denudation and thermochemical corrosion. The temperature and oxygen content in the ablation region are the main reasons for these two corrosion mechanisms. © 2022, The Authors. All rights reserved.

关键词： Silicon carbide

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Adaptive Fault Tolerant Tracking Control of Heterogeneous Multi-Agent Systems with Non-Cooperative Target

SSRN

引用

SSRN 2022年

作者： Dong, Lijing Liu, Kaige Du, Shengli Yan, Hao Shen, Haikuo School of Mechanical Electronic and Control Engineering Beijing Jiaotong University Beijing100044 China Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control Technology Beijing Jiaotong University Ministry of Education Beijing100044 China College of Automation Faculty of Information Technology Beijing University of Technology Beijing100124 China Engineering Research Center of Intelligent Perception and Autonomous Control Ministry of Education Beijing100124 China

In this paper, the fault tolerant tracking control problem of heterogeneous multi-agent systems(MASs) is studied, in which a non-cooperative target is considered. Since the target is non-cooperative, the system matrix of the target is unavailable. Therefore, the existing results dealing with consensus problem of heterogeneous multi-agent based on known exosystem matrix are inapplicable here. A neural-network-based adaptive observer is designed for estimating the output of the non-cooperative target. Then, a finite-time adaptive fault tolerant controller is developed to resolve the heterogeneous target tracking problem with actuator failures, with which the tracking errors converge within finite time. The proposed controller is fully distributed, which no longer requires the system matrix of the target and actuator fault rates of the tracking agents. Finally, the effectiveness of the developed strategies and the correctness of achieved stability conditions are verified by some numerical examples. © 2022, The Authors. All rights reserved.

关键词： Target tracking

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Enhancing Robot Teleoperation in Remote automation Production through an Event-Triggered Control Strategy

Enhancing Robot Teleoperation in Remote Automation Productio...

引用

IEEE International Symposium on Industrial Electronics (ISIE)

作者： Mengke Wang Honghao Lv Ruohan Wang Haiteng Wu Lipeng Chen Yi Chen Haihui Yuan Geng Yang State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Hangzhou China Zhejiang Key Laboratory of Intelligent Operation and Maintenance Robot Hangzhou Shenhao Technology Hangzhou China Robotics X Tencent Shenzhen China Intelligent Manufacturing Center DongFang Electric Corporation Academy of Science and Technology Co Chengdu China China South Industries Group Corporation Hangzhou Automation Research Insititute Co. Ltd. China State Key Laboratory of Fluid Power and Mechatronic Systems School of Mechanical Engineering Zhejiang University Zhejiang Key Laboratory of Intelligent Operation and Maintenance Robot Hangzhou China

ISBN: (数字)9798350394085

ISBN: (纸本)9798350394092

With the advancement of intelligent manufacturing, an increasing number of industrial production processes are transforming unmanned operations. This trend is particularly evident in factories that involve potential safety hazards, where the demand for unmanned production is becoming increasingly urgent. Teleoperation, as a core technology for achieving unmanned factories, holds tremendous importance in keeping workers safe from danger. However, traditional teleoperation strategies encounter challenges due to mismatches between master and slave workspaces, making it difficult to achieve both high precision and operation across large workspaces simultaneously. To address this issue, this paper proposes an event-triggered control strategy for a teleoperated robot system. By introducing a foot pedal as the event-triggered switch, the enablement and termination of teleoperation are associated with the activation of the pedal. Through resetting the start position, fine-grained teleoperation is achieved throughout the entire workspace of the robot. To demonstrate the advantages of the proposed control strategy, a mimicked wiring operation task scenario is constructed for experimental verification, and the teleoperation tasks are completed successfully and efficiently.

关键词： Wiring Accuracy Service robots Switches Market research Production facilities Main-secondary

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Pseudo-LiDAR for Visual Odometry

arXiv

引用

arXiv 2022年

作者： Deng, Huiying Wang, Guangming Feng, Zhiheng Jiang, Chaokang Wu, Xinrui Miao, Yanzi Wang, Hesheng Advanced Robotics Research Center AI Research Institute School of Information and Control Engineering China University of Mining and Technology Xuzhou221116 China Department of Automation Key Laboratory of System Control and Information Processing of Ministry of Education Key Laboratory of Marine Intelligent Equipment and System of Ministry of Education Shanghai Engineering Research Center of Intelligent Control and Management Shanghai Jiao Tong University Shanghai200240 China

As one of the important tasks in the field of robotics and machine vision, LiDAR/visual odometry provides tremendous help for various applications such as navigation, location, etc. In the existing methods, LiDAR odometry shows superior performance, but visual odometry is still widely used for its price advantage. Conventionally, the task of visual odometry mainly rely on the input of continuous images. However, it is very complicated for the odometry network to learn the epipolar geometry information provided by the images. In this paper, the concept of pseudo-LiDAR is introduced into the odometry to solve this problem. The pseudo-LiDAR point cloud back-projects the depth map generated by the image into the 3D point cloud, which changes the way of image representation. Compared with the stereo images, the pseudo-LiDAR point cloud generated by the stereo matching network can get the explicit 3D coordinates. Since the 6 Degrees of Freedom (DoF) pose transformation occurs in 3D space, the 3D structure information provided by the pseudo-LiDAR point cloud is more direct than the image. Compared with sparse LiDAR, the pseudo-LiDAR has a denser point cloud. In order to make full use of the rich point cloud information provided by the pseudo-LiDAR, a projection-aware dense odometry pipeline is adopted. Most previous LiDAR-based algorithms sampled 8192 points from the point cloud as input to the odometry network. The projection-aware dense odometry pipeline takes all the pseudo-LiDAR point clouds generated from the images except for the error points as the input to the network. While making full use of the 3D geometric information in the images, the semantic information in the images is also used in the odometry task. The fusion of 2D-3D is achieved in an image-only based odometry. Experiments on the KITTI dataset prove the effectiveness of our method. To the best of our knowledge, this is the first visual odometry method using pseudo-LiDAR. Copyright © 2022, The Authors. A

关键词： Pipelines

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Boosting the Efficiency and Mechanical Stability of Organic Solar Cells Through a Polymer Acceptor by Reducing the Elastic Modulus

引用

advanced Energy Materials 2025年第0期

作者： Wang, Yan Yu, Han Zhao, Dan Liu, Wei Liu, Baoze Wu, Xin Gao, Danpeng Zhang, Dong Zhang, Shoufeng Sun, Xianglang Zhang, Chunlei Zhao, Chaoyue Fu, Yuchen Song, Wei Gong, Shaokuan Fu, Yuang Kwok, Chung Hang Ge, Ziyi Lu, Xinhui Chen, Xihan Xiao, Shuang Wong, Wai-Yeung Chai, Yu Yan, He Zhu, Zonglong Department of Chemistry City University of Hong Kong Kowloon999077 Hong Kong Department of Chemistry Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional Materials Energy Institute and Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration & Reconstruction Hong Kong University of Science and Technology Clear Water Bay Kowloon999077 Hong Kong Department of Applied Biology and Chemical Technology and Research Institute for Smart Energy The Hong Kong Polytechnic University Hung Hom 999077 Hong Kong Hong Kong University of Science and Technology-Shenzhen Research Institute No. 9 Yuexing 1st RD Hi-tech Park Nanshan Guangdong Shenzhen518057 China School of Automation Engineering University of Electronic Science and Technology of China Sichuan Chengdu611731 China Department of Physics City University of Hong Kong Kowloon999077 Hong Kong Zhejiang Engineering Research Center for Energy Optoelectronic Materials and Devices Ningbo Institute of Materials Technology & Engineering Chinese Academy of Sciences Ningbo315201 China Shenzhen Key Laboratory of Intelligent Robotics and Flexible Manufacturing Systems SUSTech Energy Institute for Carbon Neutrality Department of Mechanical and Energy Engineering Southern University of Science and Technology Guangdong Shenzhen518055 China Department of Physics The Chinese University of Hong Kong Shatin999077 Hong Kong Center for Advanced Material Diagnostic Technology and College of Engineering Physics Shenzhen Technology University Guangdong Shenzhen518118 China Shenzhen Research Institute City University of Hong Kong Shenzhen518057 China

Organic solar cells (OSCs) are regarded as one of the most promising flexible power sources due to their lightweight and flexible properties, with the improvement of photovoltaic and mechanical performance. To improve the current density and power conversion efficiency (PCE), mPh4F-TS (TS) and PYSe2F-T (PA) are introduced into the binary host, PM6/mPh4F-TT (PM6/TT) as third components. It is demonstrated that the corresponding ternary devices, in both rigid and flexible devices, achieved superior efficiencies (19.6%/17.7% for PM6/TT+TS, and 19.2%/17.4% for PM6/TT+PA) outperform the binary counterparts (18.3%/16.4%). However, distinct differences in mechanical performance are observed between the polymer acceptor (PA) and small-molecular acceptor (TS). The PM6/TT+PA significantly improved the mechanical stability of flexible devices with a lower elastic modulus of 3.6 GPa, while the PM6/TT+TS resulted in the opposite effect with a higher elastic modulus of 5.5 GPa. Through in-depth investigation, a clear correlation between the elastic modulus, crack density, and mechanical stability of the active layer blends is successfully established, revealing the key role of reducing the elastic modulus in enhancing the mechanical stability of flexible OSCs. This study provides important guidance for the development of flexible photovoltaic devices with both high efficiency and mechanical robustness. © 2025 The Author(s). advanced Energy Materials published by Wiley-VCH GmbH.

关键词： Organic solar cells

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